I'm a Construct 2 developer and I have created an online highscores table for my games.
It's so simple, mobile adapted and let me to add the score of my players without make him to login or create an account (that's why I decided to make it my own service). I only send a post to an url with the points encrypted in a different way for each game and the score appears on the page:
The user experience is good: for example, in Phonegap the highscores table appears inside the Game.
Well, the next month I will launch the service for everyone (probably the next week will be working the beta version).
The service will be for free. If you are interested, I will enable the first 100 games for the beta phase (I need to test my server before to launch it ).