Conures are, in general, more likely to be total cuddle fiends IF they are handled frequently and with care. I've also noticed, in my experience with a decent number of conures, both fosters and my own two (three if you count Yamato the quaker parrot, seems the verdict is still out on the quaker as conure thing) that they can be a bit emotionally sensitive. They require a gentle touch, especially when younger, but if you gain their trust they can be some of the most loving birds, even if they can get moody sometimes.
Granted, there are always oddballs, this is just what I have generally noticed about conures as a whole. Oh, and that they can be total goofballs and brats when they know they're in a safe place with someone they can trust.
As for the green cheek specifically, they are a quieter conure most the time. Don't take this to mean that they can't really go off from time to time however! Nero has startled me many times by going from totally quiet to sudden, loud, honk noise fuss mode without warning and for no apparent reason (I call this a UBE, Unidentified Bird Event) but overall, they are a lot quieter than a sun or jenday. Most green cheeks I have encountered love to cuddle and try to groom you and tend to be rather affectionate. Some will be affectionate for a bit then decide suddenly that they're done but that's birds for you!
Green cheeks are also very clever and can sometimes make you question if you're training the bird, or if the bird is training you. This clever and curious nature can get them into trouble so they should be well watched any time they are out of the cage. Nero has gotten himself in some pretty interesting situations, from getting stuck in an empty glass because I looked away to find my ringing phone (I had to turn the glass on its side for him to reverse his little red butt out of it) to managing to somehow get himself inside of my computer case while I let him out to change his and Virginia's food (It was off at the time thankfully!) so prepare for some antics, they are possible due to how curious some green cheeks can be.
The big draw back of green cheeks I have encountered is that, if they decide to get nippy, they tend to have VERY sharp little beaks. I get pinched from time to time by Nero and, even though he rarely breaks skin, goodness it stings when he pinches me. The little brat then laughs because he made me jump.
It seems you have already done a lot of research so you know about the messes, with almost any conure, and most any parrot if I'm to be honest, there's a chance you will have to deal with the disgusting looking thing I call "bird soup" which is when you end up with a bird who likes to put their food, toys, all that in their water dish. You can clean it, go shopping for a couple hours and then come back to that and wonder how the heck they managed to make the water that gross in such a short period of time. And it doesn't tend to smell so good either even if it's fresh.
Another heads up about conures, some others may do it but I've mostly seen it with conures, is the morning mega-poop. A lot of conures tend to hold their poop at night for some reason then, in the morning, drop a poop bomb that's almost the size of their head and it's made even me, who has cared for many birds of all sizes, gag a bit just from the shear size and look of it. So beware of that one and try to make sure they poop before you take them out of the cage in the morning otherwise that mess is gonna end up on you or your stuff and it ain't fun to clean up.
