I'm a Blue Flame disciple - got their oval, stainless, twin spout, road legal (but with removable baffles - 4 in/out options for various tones & loudness) cans and link pipes on our Fazer 1000, Fazer 600 and the Aprilia RSV Mille. Quality and durability on all of them is excellent - oldest is the RSV exhaust, which we bought in '05 (or '04) and which has done 20k miles, with a lot of track time.
The systems are quiet enough with baffles and caps in that they annoy no-one, but give a deeper tone. On all 3, we've now drilled a 12mm hole in the lower spout blanking cap, and run with the top baffle fully in place (they both come out or go in, in about 10 seconds each) - nice noise, but not too loud and never been picked up at MOT or at track noise tests.
We also think they look great (photos posted already here on other exhaust threads) and to cap it all off, the most expensive (most recent) one was I think about £170 direct from Blue Flame - oh and fitting's a doddle.
There's a few more Fazers on here with them and I've seen no bad feedback yet.
All in all, we can't fault them.