The X-Finity 600w died on me after a case change...I am not too sure how I fried it or could have fried it. I guess since it worked before a case change it was my fault but I did everything right so I'm not sure.
The X-Finity has only 35A on 12's and 600w's for 70 bucks while the RP550 has 35A's on the 12's and 550w's for around 50-55bucks usually. So thats why I bought an RP550 after something happened to mine.