I've probably ridden as many stallions as I have geldings and do not mind the difference. I like that keeping a horse entire means you have to pay attention to his opinions and respect what he tells you--kinda reminds me of my Dobies that way--so I entirely "get" keeping a horse entire WHEN you have the experience to do so.
That said, I do think you are better off with the 3-yr-old. Mentally he should be ready to work and actually enjoy it. Since you are not worried about showing, if he is serviceably sound and has an attitude about life that you like, I would not worry about being "perfect". If you've got a good vet whose opinion you can trust and a good farrier who really knows feet and legs, get your second opinions from them! If they find no serious faults, that is what I'd want to hear if it was me looking at this fellow. Is he sound enough to do what you want to do with him and smart enough to learn to do it; do you like his attitude about people and life in general; is he someone you can get along with over the long haul--these are the questions I'd be asking myself.
Conformation-wise what matters is are his faults going to interfere with what you want to do with him? Because ALL horses have faults. The key is to make sure that his faults won't hold him back so much that they won't allow you to enjoy whatever you want to do with him.
JMO
Rusty
edited to add: I should have mentioned that for some reason I don't quite like the eye on the 2-y-old. I don't think I quite trust him. Of course, these are only photos and the animal in the flesh may be quite a different matter, so take that with a grain of salt. Between him and the QH, I'd take the QH. He's got a sweet eye. But the Andalusian/QH is the one who is ready to go to work. Again, just my opinion.