we make our own UGF systems here and use powerheads for the circulation, i also house an undulated trigger in a solitary tank with a powerhead only for circulation and to promote oxygenation in the water, the trigger is messy and UGF's would clog over time.try and go for a wet/dry system with an external sump. as to which brands we get many different varities mainly from the far east and i have no problems so far.
incidentally would you know of any good marine fish retailers in london? i used to live there and need to order some livestock.
hope the info helps.