Kind of both, but it is a good thing.
They hit hard and eat every time. The hitting hard is the aggressive feeder part. I make sure to get the prey item right in front of them quick so they don't miss. They have good aim though. My BP will be striking all over the place so she is an enthusiastic feeder, which boas are as well, but they hit like a freight train. BAM. That can be intimidating for some people. A big snake that nails their prey.
The other thing is they are always wanting food. Two of my boas will nail the doors if I walk by at night hoping for food. I put drapes up and that prevents it most of the time.
I have hook trained all my large snakes (my boas and my carpet python). Feliz, my dwarf BC, can be striking at the door or ready to and I tap him and rub him with the hook for a few seconds and he turns into a puppy dog. I can take him right out and he is friendly and curious.
Absolutely hook train! If you do and handle them with respect and care (like I do all my snakes) they are gentle and docile and fun.
Again, not a beginner snake. However, once my boas know food is not coming they are wonderful snakes to handle.
I am not trying to scare you, or anyone else for that matter, but boas deserve respect and knowledge of what you are getting when you acquire one.
If you understand that, and get a younger boa so you can grow together (especially if you are new boas), I highly recommend them.
If size is an issue, there are many species of dwarf BI's. They are not all as calm as the bigger BI's but it can be individual boa specific as well type of genes, etc. Feliz is a Venezuelan Dwarf BC, but they are hard to come by. If you can find one, they are amazing. BIG BC temperament in a small body.
Feliz is is almost 8 years old and he is about 5 1/2 feet and 2kg/4ish pounds.