We also use FFRS, be lost without it now, VACS didn't have good back up and failed a lot. MYCFSCREW, whilst being free, didn't offer the same features as FFRS and isn't a company per say, just a donation based program. Not saying that its bad, just not what we wanted and the cost was no more than a cheap phone plan. FFRS has very very good backup support from its local distributor and the tech support is 24/7 and like Adam said, they take a lot of suggestions on board and add them to the program. Its invaluable now for crewing, took a couple months to get people using it all the time, but now we have full take up of it.
Really though the choice is yours.