Hey Dan. I appreciate your comments. I have never seen Ares Sci0fi as a competitor to Defiance. The two games are quite different. I'm not looking for all the extra chrome that comes with Defiance. Ares Sci-fi (reduced wound fast play variant) allows for 50-100+ figs per side with no problems. Defiance iusn't really designed for that.
From having played the basic ARES game a few times myself, I would actually say that Defiance allows for more figures per game, given a set amount of time. Though, as you suggest, the quick play version of ARES is faster, and probably makes things about even.
The major difference between ARES and Defiance is that the former is based around individual activation and the latter around unit activation.
If you did want to make Defiance primarily focused around individual activation - which you can do, by choosing lots of vehicles and elites - then it would definitely take longer to play than ARES for the same amount of figures.
-Demian