Well, I suppose it depoends on a) weather conditions, b) ventilation c) possibly, the design of the tent and if you do any cooking/heating in the tent. I've got a double rainbow, which is single skinned, although I have a breathable, clip in liner that is made or it. The mesh inner, therefore, should deal with the condensation as some folk have positted. but I've sewn in panels of solid inner tent material because...basicaly I'm a wimp and want a warmer tent. I've got to go out in it yet, having just bought a replacement crosspole sleeve off Tarptent.
Although the stitching, fitting looks a tad amateurish (a lot amateurish!) I feel a lot more comfortable with the thought of facing the elements in it.