I know this thread is old but I am replying with my 2 cents worth for future reference. I purchased the 5mm gloves a few weeks ago and finally got to use them for the first time today. I had on a 7mm wetsuit. I bought them to go with my drysuit mainly. Quite often I find myself needing to take my gloves off and on during the dive for different reasons [to make gear adjustments underwater, with full winter gear on, is impossible with mitts or thick gloves.]
I love the ease with which these went on and off in the water today. I did have a big problem with zipping the end of the gauntlets over my sleeve. For fear of breaking the little pull at the end of the zipper, I just left them unzipped for the dive. The water was 46* and I was in for over 45 minutes. My fingers and hands - though soaked - were toasty warm throughout the dive [note that I do wear a thin pair of silk glove liners underneath for the undressing part later - the liners, even though wet, will keep your hands warm a lot longer when you are taking off the gear in the wind by your vehicle].
If any Waterproof designers are following this thread I would suggest either putting on a very strong zipper pull and longer pull strap, or making the very end of the gauntlet wider to fit over a thick sleeve better. These gloves are plenty warm and tight, as is, around the hand and wrist. Maybe the forearm doesn't need to be as tight. Of course they couldn't be called waterproof then.
These are my 4th pair of winter gloves I have tried and I love them.