Many gaited horses are never allowed to canter, or riders make them wait until they are older to ask. The theory is that if you allow them to canter, they won't want to gait because it is harder for them to do. IMO that theory is totally false, I've ridden alot of gaited horses that can go from walk to gait to canter & back again without any problems!
I bought my Rocky because they have a reputation for being the best all around gaited breed, but I have not had him long enough to know!
So the winner is TW because they come in so many shapes & sizes, and are so plentiful, eneryone should be able to find one that suits them. Plus you can buy a good one dirt cheap! Finally, they have such a kind and forgiving attitude! Very gentle and easy-going horses. I know many people that can load 3 stallions & a mare in a basic trailer and head to a show without any problems! You don't see that happening with too many other breeds!
I do love Morgans too, and have seen several be very successful in eventing, endurance, Dressage, driving and anything else you want to do with them. But the thing is, I don't think they are naturally gaited, it is more trained in. So I would choose a Morgan as a great all around horse, but not as the best gaited breed...