what you get with Ancestry as regards census and BMD is far better, however, find mypast is alot more user friendly and I am able to find people very very quickly, alot easier than on ancestry, but what I really really like about findmypast is that if you find an error in the transcription and report it, you get free credits, and trust me, there are thousands of errors, I have managed to accumulate so many credits now!
You can do short term subscriptions on either , which I think is the best idea. I know alot of people on here use ancestry but it can get over subscribed especially at weekends and you can't get in!