To power what? They're fine supplies, but overkill for many applications people seem inclined to recommend them for. Other manufacturers make cheaper or quieter PSUs that do the job just as well.
From what I have seen they are high quality and rock solid, and if any thing goes wrong they will replace it. I can confirm that last part since I had one of their older 510 Watt ones go bad. Told them what I found in the RMA form, and shortly after shipping in the old one, I got my new one which was even better then the original (original didn't have the PCI-E connectors, and they sent a SLi certified one back )
I've been using this TurboCool 510W SLI for a year now with no problems. Hardware configurations I've used on it:
1)
AMD x2 4400+ @ 2.5ghz
Abit A8N-SLI
Abit AN8-32x
2gb HyperX (4x512)
2gb Mushkin (2x1024)
2x 7800GTX SLI
4 HDDs
SB X-Fi platinum
Water cooling with 4 120mm fans
DVD-RW