My 2 cents: I own both the Gislaved and X-Ice (first gen though). Gislaved is less squishy feeling and has better handling (especially on the highway, it feels less squirmy). However, it's tread is not as soft and I think had I studded them, the traction would be better on ice.
If I had to choose between the two, I'd take the Gislaved over X-Ice 1, but not over X-Ice Xi2. The Xi2 supposedly has much better braking than the first gen, and the Gislaved's at best are equivalent to the X-Ice 1's for braking (in my experience).
I drive an Eos and it the only winter tires I could for a decent price at the time.