I may be somewhat late in posting this, but it seems like IL-2 has much more realistic physics compared to that of the civillian flight sim Microsoft Flight Simulator...and even X-plane for that matter, at least as far as feel goes. IL-2 seems to be the only simulator that properly spins the airplane, unlike MS, which doesn't spin right, and X-plane 7, which doesn't spin right either. Of course I have no idea what the actual planes would spin like, the closest experience is that of spinning a Cessna 152 Aerobat during some training. But using that for comparison, IL-2 just gets the "feel" of really flying. The stalls, performanace, everything seems to "feel" just right, this being based off my actual flight experieinces (which in that case I'm still a relatively low time pilot). Anyway, just my thoughts on IL-2. I have no experience with CFS.
-Kukov