Take a look through the n-key rollover sticky, people have been getting at least the advertised 6-key rollover on Filcos. I don't really think Filcos are all that expensive when you compare them to other "gaming" keyboards like the G19 (even G15's are pretty pricey).
As for Filco vs. Steelseries, I'm going to guess that most people here will vote for the Filco. Not many people around here are fond of Cherry black switches.