I will be on the GXP board for the next 3 years.
After drooling over the pictures that 5.3 Avalanche posted I had to get a Crimson Red GXP. I I decided to go with the dark pewter interior. The dealer was able to find several avaiable, but most of them had been sitting on dealer lots for 200 days or more. We found one in Indianapolis that was built in May. Road Trip! The GXP stickered for $39,700 and with the GMS pricing and GM credit card I was able to do a Smart Buy at $355 a month. The GXP handles better and the steering feels much better than the SSEI. The SSEI is better off the line, but the Northstar has more power at highway speeds. We get about 3 MPG less with the GXP, but premium gasoline is not required. Maybe it will be better after the break in period.
The wife likes the GXP a lot more and has commented that she gets a lot more looks driving in the GXP.