I have to admit that I've never used a quilt, though I considered it for a while, but didn't buy one, not because I thought there was anything wrong with a quilt, but because I already have four sleeping bags, and I couldn't afford/justify one
However, them as 'ave them speak highly of them. Cynics would say that when you've just spent £200 or more on a piece of kit you'd have to say that anyway
I have a couple of friends in the Backpackers Club who use them regularly, both for simple weekend trips and longer routes like LEJOG & SWCP, and they're happy enough
I assume you have read the book that really introduced quilts and ultralight backpacking, by Ray Jardine
He has produced two editions of essentially the same book, but has given them different titles - Beyond Backpacking and Trail Life
If you Search YouTube; there are several videos, but Search for 'backpacking quilts' or you will get all sorts of household ones and others
Probably the two best suppliers in UK are
www.backpackinglight.co.uk and
www.ultralightoutdoors.ukProbably like choosing a tent or a rucsac you'll spend ages going round & round till you're confused and bog - eyed, then realise that you'll just have to settle on something. And as usual I expect that price will be as good an indication of quality as anything
You'll also have to consider the sleeping mat and attachments for the quilt
But I never figured out what you were supposed to wear in a quilt
I can't imagine lying naked, or with just a T shirt on a sleeping mat being very comfortable. And if you have to carry some sort separate night wear like jogging bottoms/sports pants and a top then that would start to negate any weight saving
On the other hand, users say they are more comfortable and have more room & freedom than a sleeping bag, and it's easier to fold them back to have a pee
Another comment I've heard is that it's easier to stuff your Jack Russell Terrier into the bottom of your quilt, to keep your feet warm