Everything the previous poster said.
They are cuddly beyond belief,they need to be taught independance sometimes as all they want is their owners attention. They are more than intelligent enough to ''train'' their owner if they aren't careful............
They are a joy to have but very demanding, if you get them don't give the more attention than you can realistically give them for the rest of their lives because they WILL expect it as the normal and will get stressed if it suddenly changes. They can (most but not all will) also go through nippy stages which will develop into biting problem if encourage inadvertantly.
I don't have a pair but I imagine it may be a bit easier on you if you get two as they will have each other to interact with as well. It does of course mean double the training as you will need to spend time with both of them and one on one if possible. They are definitely quiet as birds go and not big chewers either so they probably won't destroy your furniture lol.
If you can get same sex if you are keeping them together in the same cage (not essential but makes your life easier), if not make sure you know exactly how to discourage them from breeding and be prepared to replace any eggs laid with fakes or prick the shells.
Loads of people on here with them who can add alot more to what I already put.