How does a nikon d3100 compare to others in it's price range?

Also, is there a better alternative? If so, what is it? I'm in the UK?

The D3100 is actually quite good. It was probably the best in its range at the time. It's been replaced by the D3200, which by all accounts is not that much of a step up. If you can find a D3100, especially as a factory refurb, you should get it. You'll be very happy.