Love it, use it regularly. Using it tomorrow, 1:30-6:00pm, high-rental time, $74 total, includes car, gas, and insurance (may not be good insurance, but at least it's some), parking lot is about 600 feet from our apt, behind the church at 2 Clarendon. Car is a Nissan Altima Hybrid.
Using it again on Tuesday, did a 12 hour rental since it was as cheap as it would have been for eight, going to New Hampshire, 150 miles probably total, cost is $74 total. Getting car from same lot. It's a Mazda 3.
Our usual car is a Volvo S40, usually runs about $12 per hour.
Since I don't often have clients for business, we have no other need to own a car. Between the cost of car & insurance and the hassles of South End street parking, we think it's worth it by far.
I agree, having it as part of a development would be beneficial for the people who live there but has to be accessible to everyone, and not hidden away in a garage or something, making it hard to access or not worth the effort.
There is a membership fee to sign up, but it's one-time. However, there is an annual $10 charge ... that goes to the Massachusetts Convention Center Authority.