I got my free 6 months subscription to Ancestry.co.uk through the purchase of the latest version of Family Tree Maker, and they work together pretty well. However I doubt that I will be renewing when it runs out - too expensive. The slight downside to the subscription is that it is only for the UK records, many of the US records are not included, but still shown, as locked, in the FTM search results. Fortunately for me I'm not interested in them.
Now, as the devil's advocate I will make a small defense of Ancestry.co.uk. If you go to the individual census year search pages (Ancestrry.co.uk/census > select a year) you can do wild card searches, even to the extent of getting EVERYONE (don't enter a name) in a parish / town or even county! (about 300,000 people in Essex in 1841 is a bit of overkill). I don't think this is possible on any other census site I've come across, but then I don't subscribe to any others.