Not everyone likes the activation system in FWC but I think it depends on what type of player you are. I've had my moments of frustration with it but I've gotten more relaxed and think it does allow that introduction of both Lady Luck and Murphy to your planning and can result in some positively cinematic situations which I think suits a scifi setting.
I think the fact that there are lists for loads of manufacturers and the unit creation system is simple has let us play some really great matchups, after all it's good to get all your toys on the table.
It scales well, our group tends to play 1000-2500 point battles, sometimes with up to 6 players and it handles this quite well but you will find yourself introducing a few house rules. Given the difference in tech between the army lists this provides some interesting matchups between small high tech forces and very large low tech ones. Given the number of games we have played and the relative parity in victories between different armies, from a very broad perspective it seems to be nicely balanced ... apart from bloody kraytonians! Grrrr. I always seem to lose to them!
My biggest criticism is that it's a tad too generic and I could do with a bit more flavour and scifi goodness.