I got Robin my male Red Bellied in 1994 as a weaned youngster from a bird store. He has been the most 'easy' roll-with-the-punches type of bird I have ever known.
He has a limited vocabulary, but is better at mimicking a variety of household noises. The natural vocals of Red Bellied and all Poicephalus are whistles, chirps, peeps and squeaks. Even though Robin can be fairly noisy at times, he is not what you'd call loud.
From my experience with Robin and Griffin, and hearing about others' Red Bellied and related species, and studying the species/genus over the years, I feel I might be qualifed IMHO to state a few basics

:
Hands on:
Some Pois are cuddly, some are not, but this is a species/genus that has POTENTIAL to not only accept, but love hands on cuddling if socialized that way from a young age. Both Robin and Griffin can be picked up not only by stepping up, but also scooped up from the front or picked up over the back, and touched and cuddled all over.
Biting:
Juveniles are sweet... After sexual maturity (and especially males) you can expect some very hard biting (hang on and grind deep and not let go) during breeding season and occasionally other times. I noticed the Poicephalus (mine and numerous others I've heard about over the years) are just more inclined to "bite first and ask questions later" as a sort of knee-jerk reaction and not something that can be completely erradicated in the behavior. That being said, a tame well adjusted bird shouldn't be biting excessively. Your bird can be bite pressure trained, but you can still expect occasional hard bites and especially during breeding season. Red Bellied and all Poicephalus have oversized heads and beaks for their body size and can pack a surprisingly powerful bite. Remember Mark (Birdman666) using the term "Sennie-tude" referring to Senegals? ALL the Poicephalus species have Sennie tude!!
Body language:
I've found that Red Bellied and other Poicephalus don't always show overt body language before biting. It's so subtle or a split second beforehand, that it might take you by surprise! Over the years I've learned how to handle Robin even while he's excited and stirred up, keeping my fingers out of the way and picking him up farther back on his body over his back and setting him on a perch quickly for example. That just comes from knowing my bird so well over the years. I wouldn't try that with my Griffin.
Phobias:
You will read (and may experience after some time) that Pois are inclined to have "freak outs" (like a reaction to being prey) a bit more easily than other species. This also makes them more inclined to displacement biting. Have one on your shoulder at your own risk, especially after sexual maturity.
Independence:
These birds can be VERY independent! IF they aren't spoiled, they are one of the least needy parrot species out there. In fact, I cannot think of another genus that has the potential to be BOTH super cuddly AND extremely independent (not needy or demanding). If on a given day I am extra busy, my birds will be okay with less attention. They'll just give up and say okay fine, and turn to their toys instead of calling persistently and being more aggressive about getting the attention they want like a conure for example. Pois are known as being resistant to plucking and other behaviors that less easy going species are more easily inclined to develop.
One person tendencies:
I've seen that Pois have an even stronger innate tendency than other species to become one person birds. The socialization with other people while very young, I suspect needs to be even more consistent and frequent than in other species in order to maintain that. Even then, the level to which this is successful I'm sure depends on the individual bird too. I have less experience in this area, as far as level of socialization vs innate tendencies, but based on my own birds, and from others birds, I do think the natural inclination to gravitate toward being a one person bird is just naturally very strong in Pois.
Activity level:
I think this one varies quite a bit between individuals. From what I see, read, and hear, not all Pois (or specifically Red Bellied) are as active as one another. Robin has many moments as a perch potato, and even when he was young he was never hyper or as energetic as related species Griffin for example. That's not to say he's always sedate, but more so than Griffin. Robin is one of the rare individuals I've ever had that I could 'probably' trust to be cage free without getting into trouble all over the house. I'm sure not all Red Bellied are that way.
Feathers:
Soft! Ohhh their feathers (especially the gray colored Poi species like Red Bellied) are every bit as soft as a cockatoo! Also, I've noticed (and avian vet said too) that Pois are dusty. Not as dusty as the powder species such as tiels, toos, and greys, but nonetheless not as 'dustless' as some species.
My Robin is the all around 'best' bird I've ever had. He's mellowed a lot with age, and is such a sweet old man lol. He is my 'soulmate' bird for sure.
I hope that helps out some
