Love it...
I just traveled England and France and set up Boingo @ Heathrow. Loved it... Saved a ton on Roaming. We had several MacBooks and iPhone 4's using it. At one time my family had 4 devices going at one time. Brilliant... The best use was on the Thames Clipper in England... My kids kept up with the school work and international friends on facebook.
As reported above I did have some minor connection issues at a few places but think the is not Boingos sole problem but rather the local provider. On a positive note from time to time it would pop up and say Boingo available here at several cafes and we could send photos and chat with family around the world for a very small price!
Once I returned to the States I called customer service and downgraded from the Global service to the Unlimited service. I don't think you can do that online.