If I were you I would go out and buy the Boa Constrictor manual. It is in almost every pet shop. I really think it is a great book. And, it covers basic husbandry in it. As a bonus....It has a lot of neat pictures in it. I would have bought it for the pictures alone.
Care for a boa is pretty similar when compared with a ball python. (In my experience balls need a little more humidity.) Max size will depend on species and sex of the boa you get.
I would personally stay away from aquarium type enclosures. I find them to be nothing but a problem for the keeper and the animal. I would buy a nice 4ft neodesha/boaphile/vision cage. They are a little pricey in the beginning. But, I really feel they are worth it for so many reasons.
Feeding will also be different slightly. I would get a boa off mice as soon as possible. I just prefer to keep them on rats as soon as I can.
Personality is pretty similar I have found as well. (Of course depending on the animals personality) Boas are great pets. Most are really mellow and fun to interact with.
Make sure to buy one from a good breeder. Pet store boas are ok. But, a few a problematic. Common boas tend to run from 75-150 dollars. I have seen some at pet stores for 199.00. That is a total rip off in my opinion.
Here are some links. Be sure to read a lot while you are here. There are a lot of knowledgeable people out there. Here are some links to help you.
http://www.boa-constrictors.com/com/com.html
http://www.pythons.net/handling.html
http://www.newenglandreptile.com/CareBoa.html
http://www.vpi.com/8VPICareSheets/Boas/BoaConstrictor/BoaConstrictorDesc.htm
http://www.bobclark.com/bcforums/forum.asp?FORUM_ID=6&CAT_ID=3&Forum_Title=Boa Constrictor Forum
http://www.theboaforum.com/cgi-bin/yabb/YaBB.pl
John
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"To be the best..........You must lose your mind."