I've never used it but I guess the most important point is if it actually works, both on a practical level (can I get a signal?) and on a social level (are people willing to put FON boxes in their houses?).

Not sure if I agree that the companies backing it have a bad reputation (Google? British Telecom?). But telco companies aren't usually the most honourable examples of corporations. In fact, of all corporate entities, they often have the sharpest business practices (product lock-ins, extensive contractual demands etc).