We flew MyTravel last month from Manchester and didn't pay for any extras on a point of principle. The 4 of us got a seat together, so £60 saved there, and we were given meals and drinks even though we said we hadn't paid for them, so that was another £60 saved, I think. We had taken plenty of food on the plane, so we came off it with quite a bit. Checking in for the return flight, we were told that we had been allocated seats together anyway.
I would say don't fall for the extras, as the food wasn't worth the money we didn't pay. For free, it was fine though! Apparently it's much easier for them just to give food to everyone rather than giving it only to the majority who paid one way or another.
We had no seat-back TVs, just flip-down screens with poor reception, so don't get your hopes up there.
Considering that we saved £800 over BA and £1,100 over the cost of MyTravel from Glasgow, I have no complaints at all and would do it again if the price was right.