Agreed, Jim. I removed my 'glider this fall, as part of a general tidy-up, and took my Raven for a short ride without the 'glider. I didn't notice any difference. When the bike is on the stand and the 'glider is mounted, if I spin the cranks, the 'glider slows down the wheel more quickly than if it's not there. On the road, as mentioned, with pressure on the cranks, I can't tell the difference.
Fossala, I run an 8-speed chain with my 38T Surly ring & 'glider -- I think that one could use a 7- 8- or 9-speed chain.