I have a pair of the ZPacks overmitts. I bought them to replace, or at least have a lighter option than my MLD eVENT mitts. However, due to the warmer weather, they are not really needed now so I have not been able to use them much.
They are smaller than the MLD mitts. They fit me fine perfect when I am simply wearing them, however, if I grab my trekking pole I can feel a little bit of pressure on the end of my thumbs. I think that if the thumb were to be about 1/2" longer they would be totally perfect.
I can layer one of my OR PL150 gloves under them but anything more would start to push it IMO.
I like the fact that they come taped, unlike my MLD mitts that needed to be seam sealed. These were my first seam seal ever, and it went ok, however, since they were still tacky even after drying they stuck together and then looked like crap. I need to attempt to peel it all away and redo them...
However, they keep my hands dry and at 0.7 oz (on my scale) they are light weight. These should fit my needs just fine since the coldest I should experience around here will be low teens, or maybe high singles, if I am lucky. For the most part though we average in the high teens to low 20's, so these with my OR gloves are all I need.
As far as durability, I dunno yet. I think that is still out on this material in general. Considering how often I actually need to wear mine though, I feel like they will be with me for a number of years...and if not, I still have the heavier/larger MLD mitts...