Agree with David.
When conditions are "right" — you will get a film of condensation on the underside of your shelter fabric — be it a double wall tent, a single wall tent, a tarp or a bivy!!
Condensation is fine so long as the drops don't come raining down on you ("interior rain"). A double wall tent has the advantage of catching most all the drops should they become detached from the underside of the fly (say with rain pounding on the outside).
But even with a single wall tent, condensation is really only an issue if LOTS OF CONDENSATION DROPS come raining down — to the point of soaking your bag — and causing it to lose its warmth. This is EXTREMELY RARE. Otherwise, a drop or ten isn't going to hurt you — but just a mere annoyance.
Part of using gear is understanding their features and their limitations.
Finally, it helps to set up the BA tent nice and taut — with the fly well away from the mesh inner. 9 stakes (not 13 unless you've got a real storm howling out there) are enough though.