I managed to get in a few rides with the Blue Grooves this weekend. My impressions so far -- they are indeed GOOD tires but they do have some shortcomings.
I tested a 2.35 F and 2.10 R on my Blur. Recall that all the tires I've used have been fairly low profiles so the BG's would be my first knobbies. The 2.35/2.10 combo proved to be heavy, slow and ponderous on flats. And on ocassions when riding through loose soil/[hardpacked] top sand, the tires would loose control and almost washed out. However, downhill speed and stability was incredible. But downhill only cosists 1/3 of my typical ride. That said, I changed the F to the BG 2.10 and R to the Exp Super 2.10. This combo proved to be better. Lighter and faster than the 2.35, the BG 2.10 climbed well, rolled over rocks well, cornered well, braked well, dowhill well, and cruised well (once up to speed). However, I still felt it was a little heavy gave up too much pedaling efficiency -- it was hard for me to get it up to speed and keep a stable cadence on the flats. I guess they "roll fast" for a knobbie -- but this is my first knobbie!
All in all, I'm impressed but not convinced that I should stick with the BGs. And I really want to like them considering all the positive comments on MTBR! It's funny that upon testing these tires, MBAction magazine came out with a comparison test. I'm not going to fully give up on the BG's yet, but I do want to try the Nevegal Lites (1.95) based on the impressive MBA rating. I'll keep everyone updated again. Thanks.