Electric Companies for Apartment under 800 sq ft

Hello!! I am moving into my first apartment post college and I am currently debating electric companies. I have gone to powertochoose.org and I had someone recommend a couple of companies to me.

I personally would prefer 100% renewable electric companies, but not a deal breaker if it not 100%.

The following companies I have looked at and have been recommended: Ambit Energy (a lot of interesting articles popped up about it even being a legitimate company when googled) TXU Reliant Southwest Power and Light Power Next

Would anyone recommend anyone better? Has anyone had experience with any of these companies, especially Ambit?