I switched to the Eureka Zeus 2 last year, and have had SOME condensation issues, but actually LESS than with my former tent–the old-style Sierra Designs Clip Flashlight. The Clip used a rainfly–which collected HUGE amounts of condensation, which rained down on the tent itself and caused a raindrop-like effect inside the tent (the “raindrops” came through the mesh). Possibly later versions of the Clip Flashlight improved upon this, I dunno, mine was Circa 1995.
Note I went to the Zeus 2, not the Zeus 1. That may make a difference, I dunno. For just a very few ounces and about $20 more, the Zeus 2 is a much more luxurious tent space-wise.
I find that in all but the most torrential downpour, leaving all the Zeus 2 vents open work to cut down the condensation. For hard, driving rain you do have to close the vent located up the foot-end wall. This of course will increase interior condensation.
The one issue I do have with this tent is how the outer door zipper tends to snag; though unlike some sleeping bag zippers that get stuck this one’s easy to untangle; also, by using two hands to zip/unzip you can avoid the snags. Seems like a design flaw to me that could be corrected by Eureka in future Zeus releases without a lot of hassle.
Skyline