I'm after a sleeping bag cover for my 400g RAB down bag which is just standard pertex. It'll be used for multi-day UK back-packing trips (October through to March) and possibly a very occasional night snow-holing and the RAB Survival Zone Lite looks ideal.
Other alternatives I've been looking at are both the new (2014) and old versions of the Terra Nova Moonlite bag cover.
I've used an older version of the (coated) survival zone - no problems, apart from it can be a bit of a contortion to get yourself in, sleeping bag zipped up and all untwisted (and I'm quite slim - if you're bulky on the upper body could be even more fun. But nothing you won't get over, and well worth the weight saving of no zip!
Can't comment on how well standard pertex works, though.
I've got one. I think mine is pertex shield. Nice small pack size. I think I've only slept in it once in a bothy when I only needed my sleeping bag liner.
I'm not a slim jim and I can get me and my 4 season bag in it.
I considered the Moonlite, but the Rab one was virtually new for a great price on Ebay.
In reply to Carolyn: I've read my post again and it's badly worded. What I wrote can be read two ways.
It is my decade old RAB sleeping bag that is made of a 'standard pertex' (i.e. NOT water resistant) which is the reason I want/need a cover for it.
In an ideal world I'd just buy a brand new RAB bag with the water-resistant 'Pertex Endurance' fabric and hydrophobic down, then I wouldn't need a bag cover, but I can't really justify going down that route.
Ah, OK, mainly my mistake - I was thinking that the "Lite" Rab was just pertex, and the normal survival zone was coated. Which I have to say didn't entirely make sense as I'm not sure what benefit a pertex bivi bag would add.
So, pretty much the system I've used, and in the same kind of conditions - down bag with normal pertex outer, rab survival zone over the top. It's been perfectly serviceable for camping in wet/cold weather, and for snow holing. Haven't used it outside of some kind of shelter. No obvious problems I can remember!