OK, I voted for GCI even though my top two are both Intamin... What gives?
Aside from Balder (#1) and El Toro (#2), I don't have any other Intamins in my top 50 wood, (Yes. I actually have Colossus at #60. Must have been a really off day, cuz I was NOT impressed.)
Meanwhile, every GCI, (except Roar west, which I just rode this year for the 1st time. It hasn't aged well or it's been maintained poorly, the design/layout seemed pretty good.) is in my top 50, with quite a few of them in my top 20.
I like GCI's creativity and curves, flow and feel. Plus, I like the trains they've made quite a lot.
Intamin has only made 8 wood coasters, half of which (the prefabs) are reportedly or IMO, very, very good. The other four (I've been on all 4) are pretty blah. GCI has 14 coasters (I've got 12 of them) out there already, and pretty much every one has been full of WIN, unless the park doesn't stay on top of the maintenance, (Hershey, BGA and 6FDK, I'm looking at you.) and that isn't GCI's fault...
So to me, GCI is the better coaster designer / builder based on consistently making high quality rides.
Ask me again after Intamin makes a few more prefabs, and I may change my tune, unless GCI just keeps getting better...