I've done a lot with the M2 since they came out, and it is very surprising how light they are for their size. I think the 80ED is under four pounds with eyepiece, which is right where the rest of the big manufacturers are. Even the big 100mm model is under five pounds. Magnesium alloy bodies are creeping down in price the same way ED glass has in the last few years.

Another difference I've found between the F-ED and M2 is Celestron's XLT lens coating on the objective. Celestron has been utilizing it for a while on their telescopes, I guess they added it to the M2 to help achieve better low-light performance:
http://www.celestron.com/astronomy/t...tarbright-xlt/