In my time associating with British Army personal I have noticed alot of issue lightweight kit. Most of it is of high quality and very effective. This is the source for their sleeping bags, patrol packs, and jackets;
Depends on the Wiggy's bag in question. I really, really like his winter bag, but his summer bag seems unnecessarily bulky for what it does. I don't think you can really get around that, though, as its designed for use as an overbag to create a cold weather sleeping system when mated with another bag. Still, for summer use, I think a more compact bag would be the ticket.
The cheapest price I've seen them thus far is $149.00 from yahoo. Lightfighter has them as well for $158. The quality of service is reportedly very high at Lightfighter, though, and the extra 10 bucks is probably worth it to get that.