I considered combining the Cane Creek barends with a pair of Ergon GP1s as well, but found it prohibitively expensive. I ended up with a set of GC2s and they are indeed excellent grips. One advantage that the GC2 has over other Ergon grips with integrated barends is that the end of the bar remains open, which is great for mounting mirrors:
When I bought a new bike last year I immediately installed a set of GC3s. These are great grips; all the comfort I expect from Ergon plus a fantastically useful barend. Lots of different hand positions. In between the GC2 and GC3 is the recently redesigned
GR2.
This past winter I experimented with a set of trekking bars combined with "barendless" GP1s. This has turned out to be the best possible combination of comfort, control, and, IMHO, good looks:
My GC3s have been relegated to the parts bin for now, but I'm sure that I'll eventually find a home for them on one of my project bikes.