Ok – I have some cash from a “leaving present” and I’m thinking of joining the bivvi-brigade. I’ve done lightweight camping for years and am currently using a Macpac Microlight. I tried a bivvi bag years ago (for one night) and didn’t really feel that comfortable.

So – for those that use tents AND bivvi on occasion – do you really think it’s worth this investment?

Should I go for one with a hoop over the head?

Will a down sleeping bag be OK, or is moisture be difficult to manage?

Any recommendations (I suspect it would have to have some sort of midge net tho…)

army issue, they’re good AND cheap, try a random internet auction site.
Snugpak Softie 9, pretty warm, light and packs down small (softie 6 if you don’t need so warm). Done me well for years in all sorts of conditions and no one will see you!
http://cgi.ebay.co.uk/BRAND-NEW-SNUGPAK-SOFTIE-9-HAWK-SLEEPING-BAG-R-Z-OLIVE_W0QQitemZ220344150572QQcmdZViewItemQQptZUK_SportingGoods_SleepingBags_SM?hash=item220344150572&_trksid=p3286.c0.m14&_trkparms=72%3A1301%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318

http://cgi.ebay.co.uk/ARMY-GORTEX-BIVVI-BAG_W0QQitemZ300287739197QQcmdZViewItemQQptZUK_Collectables_Militaria_LE?hash=item300287739197&_trksid=p3286.c0.m14&_trkparms=72%3A1301%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318

I’d stick with tent – my one man isn’t that much heavier or bigger than my bivvy (well it is a bit)

I **think** that the bivvy indicated is the same as I have and wouldn’t recommend it – soley on the grounds of no side zip – getting in and out is a complete pain – so try before buy if you can – side zip suggested.

My logic went something like
– if wet then tent much better
– if dry – don’t need waterproofness so can just sleep out without hassle of crawling into a tube in a muumy bag and then needing a wee…

If you are considering going down the ‘cop out’ big bivi bag with a hoop route, then I don’t think you’d gain much on your Macpac Microlight especially when you weigh up against comfort and convenience. Maybe consider buying a super lightweight down sleeping bag that packs down to nothing but has high warmth ie ME Dewline or lightline or Marmot Helium (there might be even better ones now).
This is the lightest bivi bag on the market I think Alpkit, and the cheapest, very highly regarded, as is the Rab Bivi bag which used to be about £50.