We owned a hybrid for 3 years before trading to a 26' hardwall trailer.
The thicker and firmer the mattress obviously the better.  Our
TrailLite TrailCruiser 19CC had a 5 inch thick dense foam mattress that
was firm and  comfortable.  The only downside was that both front and
rear beds had a split mattress - there was a narrow front piece
seperated from the larger rear section and sewn in seperately to the
fabric cover to make the whole mattress.  The union of the two pieces
was a narrow sewn seam in the mattress cover.  This front piece flipped
up and rearward and was secured when the beds folded for travel leaving
a seam that was felt by the person sleeping on that side of the bed
(the "trailer" side when sleeping lengthwise across the front of the
trailer).  It wasn't exactly uncomfortable, but it was different
feeling.

As far as condensation goes we never had a problem.  Maybe the extra
air volume in a larger trailer helps.  We got some on the windows
inside, but never got rained on from inside the tent section.  You
should still soak the tent fabric to swell the stitching to prevent
weeping at the seams, same as in a pop-up - remember you are sleeping
under the same fabric and must care for it in the same manner.

For the record, the TrailLite (by RVision) product lines had the
thickest and firmest mattress of any we looked at, and we looked at all
the major brands.

The only condensation problems I ever had on my hybrid was when all the
windows we closed and the curtains were shut - closing off he sleeping area.

Personally, we never used the furnace at night and prefer to snuggle up
under a blanket, so it was not an issue to leave a window open. I was always
the first up to make coffee so I would start the furnace and close the
windows....

john

For our part, not so far.  We think that one of the reasons is that
because of the increased size of the unit the specific RH inside the rig
 doesn't get quite so high as it would in a smaller unit such as the
8ft popup that we used to have.

As for the bed comfort, I'd be hard pressed to tell you that there was
any major difference.  The reason, however is a little different than
you might expect.  The popup we had was an older unit ...a 91.  The key
way we have is only a few years old.  The difference of ten or so years
may be part of the difference that we have.  I will tell you that what
we have is by far more comfortable.  I will also tell you that the bed
in the kiwi is a good half a foot longer than our bed at home.  Nice to
be able to stretch out.