Well, the con to me was that I
think my mileage dropped. I'm not one to watch it like a hawk mind you, but I do think it did drop a little. That, in and of itself wasn't significant enough to make me want to reset my ECU though!

If it does ever get "lost" somehow, I'd do it again. The improvement it gave far outweighs whatever small drop in mileage it might have caused.