The 5.7X28 is an interesting little cartridge. I'd like to see someone (CZ?) chamber it in a suitable rifle. I am not that impressed with the current pistol offered by FN. It is a bit large for most carry applications. I know that they champion it as a law enforcement system, but it seems that reception has been luke warm at best.
Where this cartridge may really shine is in a T/C Contender..... I'd buy a 5.7x28 barrel in a heartbeat. With ballistics simmilar to a .22 Hornet, it may never become widely used. Too little, too late...