A membership and an account are two different things. I have a Tesla account, and pay about $0.56/kWh at local SCs. If I dropped $7 or so per month on a membership, it would cost me about $0.36/kWh. I don’t because I don’t use them often enough. I have had them derate to 70kW but it was 115F in the middle of the desert, don’t know if it was my car or the charger that was dropping the speed, either way it seemed reasonable at that temperature.
Driving the F150, or even the MachE, we just have to take two spots most of the time. It feels wrong but it’s what Tesla recommends for non teslas. I’ve only used SC a handful of times, but usually get lucky and grab an end cap or the side mounted charger when available.