In our opinion and experience, the best boid (both boas and pythons) for a beginner is a Boa c. imperator.

Here are the reasons:

Almost all boas and pythons thrive in the same range of temperature and humidity. The average values during the day should be 60-65% humidity and a temperature of 28 Centigrade. At night we suggest 70-75% humidity and a temperature of 23 Centigrade. Housing at these conditions is ideal for most
boas and pythons.

There are a few exceptions though, like tree pythons and emerald tree boas, which need a very moist environment.

Apart from these two species (and some others that we may have omitted), it is no problem to house boas and pythons in the same enclosure, assuming that they are of similar size.

Furthermore, they should get along with each other. This is easily determined, as they tend to lay together often if this is the case. Evading each other and urinating small amounts several times a day are signs that they do not do well together. In this case, housing them together would lead to permanent stress. This is not only valid for keeping boas and pythons together, but it is generally valid for snakes of the same species as well.

This was the physical side of the issue. However, there is another one, namely the question of style. In our opinion, housing boas and pythons in the same enclosure is lacking style, like a wedding in t-shirts and shorts.
 

Reasons for adult Boa c. to refuse feeding without being sick include the animal being in shed, gravid, or in the mood for mating (males only) during the breeding season.

Mostly the snake keeper is responsible for the occurance of the Regurgitation syndrome due to wrong feeding!

Primarily affected:

... are neonates of redtail Boa c. constrictor such as true Surinames, Guyanas, Peruvians, and Brazilians, furthermore Boa c. amarali and Boa c. occidentalis.

Possible causes of the Regurgitation syndrome:

   a.. Insufficiently developed digestive tract in neonates of the
        above mentioned subspecies
   b.. Too large prey items and/ore too frequent feeding (the main
        reason!)
   c.. Insufficient temperatures and humidity in the enclosure
   d.. Internal parasites (wildcaught Boa constrictors)
   e.. Bacterial infections of the stomach/intestine
   f..  Nervousness because of handling or dominant specimen in the
        same enclosure

Measures on treating the "common" Regurgitation syndrome:

Definition:

The common Regurgitation Syndrome (that´s how I named it) is caused by feeding too large prey items and/or too frequent feeding or insufficient housing conditions. If there are other reasons for
regurgitation, it is NOT the common Regurgitation Syndrome.

Measures:
First check your housing: The day temperatures in the enclosure have to be between 28° and 30° Centigrade (82 to 86 degrees Fahrenheit), the night temperatures about 24° Centigrade (75 degrees Fahrenheit). The Humidity should not drop below 60%.

Any boid keeper of many years, who claims to have never had an animal escape, is lying through his or her teeth. The day comes for even the most conscientious among the boa or python keepers, when the sliding glass doors of the cage will not be entirely closed.
Ungrateful, as our charges are, they usually use this opportunity shamelessly and bolt. The smaller the snake is, the more difficult it then becomes to find it.
The dear boid keeper that has never been faced with that type of situation before is usually overcome with panic, once he/she notices the escape of the animal.

However, that is exactly the wrong reaction, because it is now important to keep a cool head and use a systematic approach.

Before turning the house upside down, examine the enclosure thoroughly to make sure that the snake has not just hid very well.

A superficial glance onto the spots that the animal normally occupies is not sufficient in this case. You should really search every angle of the enclosure (this includes the ceiling), before expanding the search. In other words, you should search the enclosure in such detail that you would be confident enough to offer your right hand if the snake still ends up being found there.

Well, we now trust your search and believe that the snake is no longer in the enclosure. Next comes phase two, in which you have a great advantage: Boas and pythons do not usually travel far, and the animal will most likely still be in the same room, in which the enclosure is located. In addition, the snake maintains its normal behavior, which means that the fugitive has hid and is at a spot in the room that is suitable for providing shelter.

The less accessible and tighter this hide spot is, the more likely it is that you will find your legless friend there. If you think that you do not need to search a particular spot in the room, since “the snake would never be able to get there”, you have already made your next mistake.

Especially popular among escapees is the bundle of cables by the enclosure. They like to climb in it and rest in it as well. Another popular spot is the space between the enclosure and the room wall. If these objects just happen to have the permissible weight of a commercial truck, then you are pretty much out of luck, hence our recommendation in the section about enclosures to seal that space with construction foam or wooden strips.

If the entire room (except for the space mentioned) has been searched without success, the cabinet or enclosure needs to be moved. There is no way around that, as bad as it may be.

But we are not there just yet, as everything else comes first. It is recommended to move every removable object after thorough examination temporarily to another room for the duration of the systematic search. That way, the room in which the fugitive is suspected to be in, becomes more open and easier to manage. In addition, this prevents the animal from hiding in such an object later, if it is not found during the first day.

This brings us to the recommendation to keep the door to the enclosure room closed at all times. This applies especially if there is a “loose snake”.

A place beloved by the snake yet hated by the keeper is the interior of the living-room couch. The snakes even get in there, which is something that should be kept in mind, if the enclosure is located in the living-room. Also, remember to look behind the heater and between its heating ribs (if applicable).

In case of a partially open window, it pays to take a closer look at it and its immediate outside vicinity. Also, keep in mind that our legless friends are excellent climbers and love height, and the search should therefore include the top of shelves, cabinets, etc.

In conclusion of the “search & rescue manual”, here a few more hints:

• It is much easier to search with a pocket light

• If the animal is not found right away, keep on checking during the following nights, as that is the time at which the animal is most likely to crawl around somewhere

• A daily inventory check to ensure the presence of all animals after maintenance work helps to discover an “escape” early, thereby raising the chance of finding the animal before it retreats to a place that is really difficult for the keeper to get access to (such as behind a cabinet, inside the couch)
   

• When a snake has escaped, it is best to leave the enclosure door slightly opened (of course, this applies only as long as there aren’t any other snakes in the enclosure), which allows for your charge to return to its regular spot
   

• During unsuitable climatic conditions, the room temperature should be adjusted accordingly (min. 23° C [73° F]), in order to prevent the snake from suffering while spending several days outside of its enclosure
   

• Providing a bowl with water is also recommended if the animal was not successfully located right away
   

• If the animal cannot be found in the enclosure room, the neighboring room has to be searched in the exact same manner, unless one wishes to abandon the search, and simply leave it up to chance
   

No problem at all. We own a dog and a rabbit. Both often linger on in the living room where we have several cages with boas.

As long as the cages are locked (they always have to be, of course) there is no dangerous interaction between the boas and the other pets.  

Notice: When you put the boas out for handling dogs, cats and other critters have to leave the room temporarily.

Although dogs and cats do not correspond to the prey pattern of Boa constrictor it doesn't hurt to wash the hands before handling the boa in case the pet has got some stroke units before, especially if your pet is a rabbit, a guinea pig or a tame rat.