I was an early Car2Go user in Austin, the first city in the US where Car2Go was available, and I loved it. I'd use it for a couple trips a month.
In the last few years of its existence I used it maybe once (if at all, honestly I don't really remember). It simply got killed by Uber and Lyft. Uber and Lyft are just generally much more convenient, and I don't remember the cost being that different.