I'm British so of course I think the West End is better. Although I have never been to a West End performance, I find it more appealing than a Broadway one. Why I don't know, but I just do. But I'm sure both are great and I would love to see either of them.
For example, if you want to see Something Rotten!, then go to Broadway. If you want to see Les Misérables after September 2016, then go to the West End. If you want to see The Phantom of the Opera, then go to whichever one is closer to your usual location.