right now dd has velcro ones. you can see in my profile pic that she has grip bands on around them so the velcro doesn't come off (see story below on why we got them at our gym). i want to go with double buckle ones starting in the summer. there is a brand that is butter soft and no break in time and less expensive than the ones she has one now, sold at the gym. i forget the name but a few girls have them at our gym already.
horror story coming up.... last year at states, one of our 7's was doing giants during her routine and the velcro came undone and at the top of the giant she picked up the other hand to try to fasten it back down. she was exactly in the position my daughter is in my profile pic and she fell, head first. our HC, who has never dropped a gymnast yet, was able to jump in and scoop her up like a baby and cradle her back and neck and she was ok, except for being scared. if he didn't have cat like reflexes and catch her properly (is there a coaches class for that?) she would have broken something serious - like her neck. i saw the video - had nightmares for weeks.
so, if you have velcro ones and you don't want to switch them out yet, get grip bands. we have teal ones that match our gym's colors.