Like you, I decided to dump my old tent (Sierra Alpha CD) for 2-1/2 out of 4 seasons (still a great winter tent, and willing to put up with the extra weight). I went with the Sierra Lightning UL for the single-wall construct, and much lighter weight.

I live in SW Pa, where humidity levels rival the southeast (65% is a dry day). That said, with the windows open for the warmer weather I have not noticed any considerable amount of condensation. If I close everything up (never fully closed as the rear window and top of front door are always open) there is a small amount of condensation, but nothing that bothers me in my down bag.