ive been running one for about a year now and ... awesome is the only word. As long as you keep your cables tight and clean they are killer.
The weight is similiar to a 6" hydro system, all the extra weight is in the rotor. The rotor is really tuff too ... has had a few bangs & still runs dead straight.
Increased power is very noticable. Make sure you've got some fat tyres behind it other wise you'll have trouble staying on your bike.
I use EBC gold pads , the absolute best by far, AVID originals are not far behind. They provide smooth and consistant modulation & performance. Pad life is reasonable & similiar to other systems.
My girlfriend's bro bought one of those Armor systems the same time I got the 8". Mine outperforms every single time.
Totally recommended, very powerful, fairly light & very awesome.