In preparation for my first tour, I'm looking to buy a sleeping bag. I ran across what seems to be very reasonably priced modern military surplus modular sleep gear such as this, as well as cheaper, not quite as good knockoffs such as this.

These are pretty appealing, since they're priced similarly to or cheaper and more versatile than commercial gear. Plus, they include a bivvy bag so I could skip the tent if I wanted to. On the other hand, I suspect they might be heavier and/or more bulky than the commercial gear.

Has anyone used systems like this while touring? Any comments or experiences, either touring with it or buying such a kit used (as in my first link)?

Tell you what, I used the MSS (modular sleep system) for a few years when I was in the Army, in the snow and in the desert. Personally, I'd spend the bucks on a nice, lightweight, easily packable bag rather than this. It's too bulky, loses loft too easily, and is not particularly warm. The bivy is nice, and it works rather well to keep the rain out, if you can find just the bivy I'd go for it. Otherwise I'd invest in a decent bag, not this.

like rainking, I have plenty of real world experience with the issue sleep system... stay away. most personnel don't store them properly (that is, they keep them stuffed), or wash them - ever. it's heavy and doesn't pack down well at all. Save your cash and get a good, commercial sleeping bag.

Fair enough. My budget is unfortunately limited at the moment, but I have my eye on an alternative. Thanks.