The total cost was in line for a similar holiday with BA or Virgin flying economy, so comparable products. The difference for us was the hotel choice, which was a class below BA/Virgin, but with a Water Park on site a little better for a 11 year old... and her parents...
The Thomson Premium was full. Not sure what the cost difference would have been - but I would hope not much as the product would certainly not be a match for the major airlines more premium stuff.