By far the best batteries you can buy for the money.
I use Turnigy exclusively for my helis and multis.
For my hex with all the gear, I am using this battery:
All of my batteries both the standard and Nanos have well over 200 cycles on them and are still going strong. Since fall of 2010 through all the mis-haps and crashes. The plastic covering is coming off, but the batts are as strong as ever.