To go along with ChargePoint, I just signed up with Greenlots. With a healthy spattering of Signet units in my area, they already have the RFID equipment for Greenlots.
My work just got a job a few miles from the only quick charger around that actually uses Greenlots to charge for a charge. It's 76 miles away, but easily doable with two quick chargers en route. The mid one is ol' reliable Eaton, and the Greenlots unit is a few miles away from my destination, so I can hit it on the return trip if I can't charge on the way there. They are close enough to only require an 80% charge at Eaton, saving me about 40 minutes.
They charge a reasonable $7/hour, which would be a full charge for an i-MiEV on CHAdeMO (I did 2 bars to 98% in 59 minutes). There are no membership fees, and the station owner sets the rate, much like ChargePoint.
I just hope the hour interval can be spread across multiple sessions. If history suggests the future, charging from that Signet unit won't happen in one shot.