They can be found both as Series 70's or 80's (check slide).
I have a Series 80. Yes, alloy frame. Lighter to pack, but snappier recoil than the steel frame Commander. Much snappier than the Government Model.
Mine is not particularly accurate. Service grade accuracy, I'd say... Slide/frame fit is loose compared my Kimbers and Springfield Armory. I have a Kimber Compact steel frame that shoots much tighter groups, even with a shorter barrel and being steel framed is more comfortable and controllable to shoot.
I'd say if you have CCW requirements for something light weight, then the Lwt. Commander (perhaps with a bit of tuning) might be a viable option if weight is a major concern. But if you want to shoot it more than pack it, you might want to look at the steel frame choices.
I have 1911's starting with GM's, Commanders, and Officers.
I've now come full circle and prefer steel frame GM's for general purpose PDW use. I find them the most controllable, comfortable to shoot lots of rounds in, and accurate. On average, out-of-the-box, they seem to be a bit more reliable, too, than the compacts, imho... With a good holster rig, they are not that much harder to pack than a Commander size 1911. My $.02...