A buddy of mine has a J-type and it looked fantastic. He had been using it frequently in Santa Cruz and he claimed that it kept him warm enough but he would get a chill after a long day of repetitive dives. I was really close to getting one, but I decided on a jumpsuit w/ a couple of hoods & vests instead.
Don't rule out O'Neill, they know wetsuits! Just steer away from their surf suits as they will compress like all surf suits do. Their dive suits are good stuff.
Bare also has a very good rep here on SB, but I've never seen their suits in person and can't fairly comment on them. I will say that I was impressed enough by what I read that I was close to ordering one online. I only decided against it because I'm 6'3" and 190lbs, not an easy size, and after the hassle of getting it down to Chile I needed to be sure it'd fit. I just ended up getting a lesser suit locally because it fit.
I cannot comment at all on the Xcel. I have no experience with them.