When I provided my original response I distinguished between the ARNG (which I know a little about) and the AIRNG (which I know almost nothing about). I think that we are in danger of confusing them again. Where the USRNG and USAR are concerned, I have to side with those posters who have suggested that, soldier for soldier, our Reserve soldier attends organized military training for more days out of the total year, and is probably better at basic skills and in particular in NCO leader training. ARNG and USAR I would suggest have a much broader total range of skills(taking all MOCs together-not soldiers as individuals...) and are familiar with more types of modern equipment than our Res would be. As well they probably benefit from greater use of simulation and distributed learning, but both of these are definitely improving in our Reserve as well.
While a large number of ARNG and USAR have former active time, I'm not certain that we can say "most" are former active duty. Certainly I would say a larger proportion than we have in the Res today (although that seems to be improving).
However, as I also tried to point out, the very high number of ARNG/USAR soldiers deployed on OEF/OIF will change both of these observations and we may be in for a big shock. No time to rest on our laurels! Cheers.