In one sentence: Good for the most part, but often overpriced.
Detailed breakdown:
RAM: Usually Overpriced, high latencies, on even their high end sticks, command price premium for no reason.... 8/10 times i would say you could find better sticks for the same $$$
Power supplies: AX series, decent, but there are better options for all of them.
HX series, Better voltage regulation than AX series, better overall, as long as you don't care about Gold, these are better units.
TX, There are cheaper alternitaves to all of them, EXCEPT, the TX950 which offers a good value for the price.
VX, being phased out anyways, kinda dated now, and have been surpassed by their competitiors.
CX, CX400=epic win, every other CX=meh
GS: meh, there are cheaper/better options
Cases: Can't really comment here, they are high quality, and looks are personal preference.
CPU coolers: Overpriced for the performance they offer. H50 barely preforms better than standard air coolers. For the price of an H70, you could have spent $20 more and got a real water loop.
Customer serivce: Top notch. In my experience, they have handled everything well.
Rebates: i have got 4/4 back from them.