I have been using NOW TV for about 2-3 months and its OK. It wasn't hard to set up and its only a tiny little white box, which cost a whacking great £9.99 to buy on ebay !
The quality of the pictures are not marvelous, but perfectly adequate. If all you want is to be able to used the various i players, like the Beeb, CH4 and ITV, its much cheaper than buying a new "smart" TV.
The packages are much of a muchness......mostly satellite channels, that I personally don't want or need. But you don't need to subscribe to any package if you don't want to, But if you do, there is no contract, and you are able to cancel after the first month without penalty.
But, if all you want is the i players, than its free, after the initial £9.99.