I've tried a babyhawk and toddlerhawk (which is just a taller babyhawk I believe) and found both to be comfortable and my dd is nearing 3 years. By this point the babyhawk is getting short on her, but should work fine for you, or you could get a toddlerhawk and roll the bottom to shorten it as it will probably be too tall for a long awhile. The fun thing about babyhawks are designing them

I haven't tried a kozy, but I know lots of people use them with toddlers. I believe the body is 17inches wide by 22 inches tall, which is quite large. and they are made of canvas which is very supportive. If you order a new kozy from her website you can get regular length waist straps and xl top straps for easier tying, though lots of people do fine with regular length top straps too.
I've also tried a beanslings which was very supportive, but they aren't as easy to come by new, and I wasn't fond of the shoulder strap angle.
Babyhawk or kozy are probably going to be easiest to buy new, and also are less expensive than some of the other brands. You can find pretty much all of these brands used for less money on thebabywearer.com FSOT forum. Buying used is good because sometimes you need to try a couple carriers before you find the perfect one, so it's obviously less expensive that way.
I guess I'd just start with whichever brand appeals to you most looks wise and which brand is in your budget.