Was the American Revolution successful or a failure?
It would be very difficult to argue that Revolution was a failure. You could argue that it did not accomplish everything that it should have, but you would be hard-pressed to say that it was not an overall success.
You can argue that the Revolution should have led to a truly democratic society in the US, one in which women and African Americans were treated as the equals of white men. Ideally, this is true. But there was no way that was going to happen at the time and equality for all was not one of the goals of the rebels.
The Revolution was a success because it achieved what it was trying to achieve. It was meant to gain independence for the United States and it accomplished this goal. When some movement accomplishes what it sets out to achieve, it is a success.