I got Freesat as I live in an area where freeview reception can be a bit ropey depending on the weather. I am assured that Freeview reception will be OK after switchover, so really it's only a temporary thing. I get BBC and ITV HD from it , but recent changes to the BBC encoders mean that the BBC 'HD' pictures can be barely better than BBC standard definition normal pictures. In terms of content there's numerically more channels, but you don't get channels like Dave, Virgin 1, Sky 3, Fiver, Five US and Quest which do have some good shows.
If you can get a good freeview signal, don't bother, otherwise go for it.