120 are essentially for kids or midgets (can I say that word outside "the lounge" forum?), a pair of 180 Mexican's are the best. Since they are stretchy they are less likely to come loose on a long work out.
In my old gym, we only let the little girls use the shorter hand wraps. All the grown men use 180 or longer.
Mexican types are def better. I hate having to pull the gloves off to re-wrap the floppy junk wraps. Elastic types don't do that. I like the longer wraps because they protect my knuckles better.