Years ago the thought was a single strong 12v rail was better than multiple rails. I believe power supplies have come along way since then and to be honest as long as a power supply does well in real testing I don't even look at that anymore.
I'm sure you have seen this site before but here is everything you ever wanted to know about power supplies. It lists manufacturers as well as linking to testing sites. It's the most comprehensive easy to use listing I know of.
http://www.realhardtechx.com/index_archivos/Page541.htm
Another useful link.
http://www.overclock.net/t/738097/psu-review-database
And the tier list. It's not in any way perfect but it is a good general guide.
http://www.eggxpert.com/forums/thread/323050.aspx
In my opinion there are a few brands that are hard to find a bad model of. Corsair, Seasonic, PC Power and Cooling, XFX, Enermax, Silverstone, OCZ, and Antec.
In the past OCZ and Antec both have had models with quality issues but they seem to have fixed most of their problem lines in the last few years.
Rosewill has some good lines here recently but they are not overall good enough to recommend by brand in my opinion. Some models are good though. Mostly the Sirtec and Super Flower made units.