I used to have a pair, but again this was pre-takeover by Jackson. I hated my Gams, but then I was also over-booted at the time, so it's difficult to say whether all my issues related to the over-booting or the boots in general. Other people at my rink swore by them though, although I would also say that Gams were the boots the local fitter pushed, so that might not be surprising.
I also can't compare them to Jacksons as I've never worn them. I moved to Riedell after the Gams.