I think heosat also has a special deal worked out with Powershop so it's worth contacting him as well to get $75 off your first bill? Correct me if I'm wrong.
Having been on Powershop for a while now I regularly get 31% discount powerpacks. Due to my charging requirements, I'm hovering around 19c/kwh - and that's anytime, not ToU. With no service charges either. I love it!
Have fun switching guys - they are a fantastic company!