In a word: YES! There is (IMO) a substantial difference between the two carriers. I'm going on the assumption that you're talking about the Babyhawk Mei Tai as opposed to the Babyhawk OhSnap Structured buckle carrier. I'll talk about all three, though.
The BH mei tai has long straps that tie around your waist, and over your shoulders/across your back. It is a wonderful carrier for a baby up to a year or so, about 20-25 lbs (it is safe for much higher weights than that, but IMO, not as comfortable for bigger babes as something with a structured waistband and shoulder padding). It has a nice head-rest for neck support in little ones.
Pluses: Many different ways to tie it, totally adjustable for different sized wearers, snuggly, secure and hands-free for babies right from birth. Good for both front and back carries. Pretty easy to BF in.
Minuses: Long straps can be a bit intimidating to tie at first, long straps can drag on the ground when tying
The BH OhSnap is a soft-structured carrier (SSC). It has a padded waistband and back-pack type shoulder straps. It has the same body and head-rest as the regular babyhawk.
Pluses: Very comfy for bigger babies. Quick and easy to put on. Relatively adjustable for use between different wearers. Great for front and back carries (although I find SSCs really shine in back carries, I find them a bit uncomfy for front carries, unless I can cross the straps in back). Great adjustability in the waist-strap w innovative extra adjust straps to change the angle of the waist-band. Pretty easy to BF in.
Minuses: Not safe for newborns and smaller babies (the sides gape open when a child is legs-in). Body is a bit on the short side, so as your babe gets taller (over 18 mos or so) the body may not be sufficient for them.
The Beco Butterfly is an SSC as well, but has a panel between baby and the wearer. This allows you to put the baby into the carrier, and then put the carrier on. It has a structured waist and back-pack type straps
pluses: Very easy to get baby on your back. can transfer carrier between wearers without taking baby out. has an infant insert for newborns. Higher body, making it usable for toddlers as well as little ones.
minuses: the buckles are weird and fiddly, IMO, and cannot be undone one-handed. Hard if not impossible to BF in, due to the fabric between mama and baby.
Whichever one you get, I'd def. get a RS as well. For me, I find a mei tai plus ring sling to be a wonderful combo for babywearing that would meet all your needs up to 12-18 mos or so.
ETA: The MT would be fine for a bigger mama. I'm a size 16 and had LOTS of strap left over. If you are worried, you can get one with XL straps. I can't speak to the other two, as I've only borrowed, and can't remember the length of the webbing.
I have a Storchenweige RS and I LOVE it. it is completely unpadded and made from woven wrap material. It is a total work-horse, looks gorgeous, and is fairly easy to get comfy, once you learn it. I prefer unpadded RS in general. I find them much easier to deal with, but that's a fairly personal decision. I know people like slings by Sleeping Baby Productions, as well the Maya Wrap lightly padded version and the Sakura Bloom brands are good, I've heard.