Gore-Tex bivvy bags are great. No, I mean utterly incredibly amazing. Except for two things: It's difficult nay, impossible to change your clothes inside, and there's really no place to store your pack, hardware, and boots. (If you're climbing) I think that's where a basha comes in.
I use a bivvy bag in the winter, as it actually adds a few degree's warmth to my bag, which also happens to be down. (I couldn't afford a gore-tex down filled bag)
When I was a bit younger, I used to take my gore-tex parka and zip it up around my bag's footbox, cinch the hood, and it did an okay job of stopping the bag from soaking up too much condensation from our tent. And since our tent is a TIGHT two man 4 season, I was always pushed right up against the wall, so I'd wake up in the morning with a good portion of my down clumped and damp from the condensation. Heh, I used to take all are food bags and random stuff from my pack and line the wall as a barrier between me and my bag.
Ahhh....then I stole me Dad's bivvy, and that problem is no more. (When I'm in a tent)
His is a bit older, so the hood cinches shut, but newer ones actually have a flexible pole around the hood which raises it off your face, and does a bit better of a job draining.
And yes, I'm just making a comment about bivvy bags, telling of my experience, and not telling you where to buy one, because hey, I'm not in Europe.

(I wish I was!!!)
Cheers mate,
Adam