Only been on one while assembling it for practice.
Unfortunately no one I know in my region owns one, so trying a night on one isn't an easy option, not to mention it's an expensive piece of climbing kit - one does not loan such things lightly.
I'm relatively slim, ~65kg, was thinking about a Metolius bombshelter double, would be used in one of three cases:
- Just me on it
- Me and 75-85kg person
- Me and 55kg person [my partner says sleeping on the ground is challenging enough, she's not convinced it would even be possible off the ground...But I think after a hard days work...]
I suspect comfort is mostly a case of fabric tension and your weight, I figure one can probably make do, stuffing lumps of clothing and sleeping mat into just the right position to align ones back and neck in a good way [back has been a bit irritable as of late, as I've mentioned around UKC!].
Bear in mind you only use a Portaledge because there is nowhere else to lie down; finally getting to do so is usually heaven. Its hard to be objective for that reason, but they're as good as a bed in my experience and far more comfortable than any tent/ bivvy I've ever slept in. The annoying bit is when one of you sits up and the whole thing moves.
In reply to needvert:
For small people (i.e <70kg) who are happy to sleep on their backs and mainly good weather I'd go for a double from Fish Products as it will be much lighter and easier to put up. Assuming you are off to Yosemite, Fish will post it to the Yosemite post office.
For big people or if you plan to have to sit out storms with lots of cooking and gear then something bigger. (Or ask Andy K.)
In reply to needvert:
On a small ledge you won't be able to turn over all that easily. I guess if you sleep on one side most of the night that would be fine. If however you tend to change slides a lot it might be a bit tight.
generally I found sleeping in a ledge pretty comfortable, but admittedly the majority of the time I have slept alone on my fish double. Because of the fabric of the bed sagging (I think this still happens a bit on the ledges with a spreader bar) everything tends to graviate towards the middle, this makes sleeping on your back a bit more comfy as you are more stable. This happens more so with two people on the ledge and you will find yourselves generally pushing against each other (great for staying warm).