I don't have experience with all of these, but have asked the same question. My cousin owns a cloth diaper store and sells carriers and she highly recommends the Beco over the Ergo for back support, and I can't remember why, but she recommended it over the BH. It seems to be a popular pick around here too.I just got mine, and its pretty amazing.
Well, I'm a woven wrap lover so that's my favorite ;-)
As for mei tai vs. buckle carriers - do you want to tie or buckle? I personally prefer tying as I feel like I get a better fit. Other mamas find buckles to be easier to use. The babyhawk may not be as comfortable for you as some other options that have padded waists.
You can do a higher back carry in a mei tai or woven wrap - depending on your LO's size, that might be a nice option to have since being lower on the back doesn't offer as good a view).
I have a BH & woven wrap & just got a Beco yesterday.
I like the Beco a lot better than the BH. I find the BH straps would keep slipping as Ari got heavier, & I was getting too much pressure on the waist strap too. The Beco is soooo much more supportive. Also, the BH straps are a PITA for out & about. I usually use my ring sling for out & about but I like the Beco better than the BH for this too. Also, DH could not get back carries right in the BH but it's really easy in the Beco.
I like my woven for high back carries & use around the house. I especially like it for wearing him down to sleep - I can pull the wrap up around him to snuggle him up, & use it like a blanket so it's less jolting of a transition down into his crib or PNP.
jackieobride:Awesome thanks! It seems more compact & neater (less straps hanging around) than the Ergo too.
The Beco actually has more straps then the Ergo does. Other than that, it is more compact and trim than the Ergo. I have both.