Who has used both and who replaced their Exped for the Big Agnes? I read the review of the Q Core SL and in spite of the negatives it appeared that many folks went with the BA.
Have you seen this thread? http://www.rokslide.com/forums/showthread.php?t=8307
To sleep comfortably I need a wide pad. So the under size / over weight issues with the Q-Core SL turn me off. I was watching to pick a SL up when on sale or discounted, not anymore. I can't complain at all about my DownMat UL 7 or my kids SynMat UL 7s.
The 3 wire is huge. there is a video where 2 guys crawl out from inside it. Its a shame BA discontinued it
http://www.prolitegear.com/site/big-agnes-3-wire-bivy-review.html about 3:40 in the video
If your biggest concern is the use if a pump bag then the ul7 is by far the best choice. BA has one but its a tie on one and not efficient at all. The exped clips on and two bags and its full. Easy choice given this criteria
I agree the Schnozzle Pumpbag works great. You just have to hold it correctly and not kink the Schozzle. (Why do I suddenly feel vulnerable?)
If you want to got to one pad and save some weight over the two you are carrying look at the Exped SynMat UL 9. It is 3.5" deep like the Q-core SL. A long wide would be lighter than the two pads being carried, maintains a high R-Value, is a deep and comfortable pad. While not the lightest pad out there it would be a weight improvement over the two pad setup you are carrying now.
If you can, do as KMD did and lay on pads side by side at the store.