I've been following this thread - I love your "prospect" threads, B2H! They're so adorable, educational, and just all around make me really excited for you! :)
Anyway, in following this thread, I have a few thoughts:
First, I really love that paint gelding Drafty posted. I used to work at a summer camp with horses and kids, and that paint guy just has the look of a really tolerant horse. The kind I would have loved to work with on a daily basis. So I'm a bit biased!
I love how his legs are really solid and big boned for his height. One sees far too many QH/Paint-types with these little spindly legs that look like they're going to break with the slightest exertion! haha
Then, there's Buzz. He looks like a real sweetie...BUT. This, again, is totally a personal opinion+biased worldview from me, but he -in the way he's built- really reminds me of the horses we would get in at camp who were a struggle to keep sound on a daily basis in very light work. That does not mean, AT ALL, that Buzz is going to be a struggle to keep sound, but again, he has that really straight "spindly" legged QH-y thing going on that scares me for over the long term. That's just my opinion and as we all know, horses are continual surprises in how they can overcome/compensate for physical weaknesses!
My other thought about those two horses in particular is that, in terms of more english-y events, the Paint appears to really be built uphill (withers higher than his butt) while Buzz appears to be built significantly downhill (withers lower than butt - very common amongst the stock breeds). An uphill build is more likely to be paired with a horse that will be easier to collect/has a natural balance about his movements and may have an easier time jumping (easier for him to lift up that front end to get over a jump) while a more downhill horse is more likely to have difficulty getting and staying somewhat collected, etc. For english-type riding, you'll probably want a horse that's level or uphill, just to make english riding easier on both of you from a collection/jumping stand-point.
That all being said, my own mare is built VERY downhill (she's 14.1hh in front and 14.3hh in the back! a pony in front and a horse in the back, hahaha) but her hind end angles are such that she can compensate for her downhillness and she actually moves very "uphill" and is naturally "collected". Having a hind end that can compensate for being downhill is not very common (it's called "the golden triangle" - basically the coup, point of hip and...that other one, are all equilateral to each other) but it's not impossible, for sure!
Anyway, those are my somewhat scattered thoughts. Hopefully that all makes sense!
And for sure, the horse that's right for you is going to be the one you enjoy working with the most, whether or not his conformation makes things easier or harder for you two. The most fun is not always the easiest fun, I certainly know about that! :)