I've had the ACSI card every year for the last 6 years.
Last year we used it 3 nights near Barcelona, bit silly wilding around there.
2013, didn't use it at all.
2012, met up with some Spanish caravanning friends at a site in Santa Pola. I paid cash & it worked out 1 euro less per night than ACSI.
2011, I needed a Gaslow fitting to be sent to Spain, I contacted an ACSI site at Isla Plana saying I would be there in 7 days & would be having a parcel delivered. I didn't tell them I was staying on the beach a couple of km down the road!.
So, all in all, I'm out of pocket having ACSI but it could be like
insurance etc.,.......When one needs it, one hasn't got it.
I'll probably join up again this year.