I went to visit NYC in 2012 and was so surprised by the lack of clean toilets around... I would've paid $5 for a good, CLEAN toilet. Usually I just go to Starbucks (works well in Europe), but I found them pretty horrible in NYC..
I go to New York City all the time (but I don't live there) and I've never had an issue with finding a clean bathroom, ever. Boston is a different story though I've only been there a handful of times.
Walk into Starbucks or McDonalds, always worked for me. Never had a cleanness problem. I usually only pee when I am in an establishment as a customer though.
I'd use a service like this.