I had one of those FSA on my fixed gear. They're okay but not great. Got a bit rough after a couple of months. Nothing major but I replaced it with a UN54 I had kicking about to be on the safe side and it's been smooth as silk since. The Shimano is a bit lighter too if that concerns you.
You can get a UN54 from
Parkers for £12.75 with free postage, which is only £3.50 more than that FSA when you take the postage into consideration. Worth it for the peace of mind i reckon.
EDIT: Just realised the free postage from Parkers is only on orders over £50. Still, it's only a couple of quid and worth it IMO. Shimano BB's last for years.