Both are worth it. I have had both. I got more use out of Extra Innings because its just more convenient. Laying in bed watching west coast games etc. I think I paid 120 for it. MLB.Tv works great but I get sick of sitting at the CPU and always feel like its a tad lagged. Plus they have too many bells and whistles which kind of takes away from the game.
In closing, both are worth it for their respective prices...I enjoyed Extra Innings more and would pay the 200 as it pays for itself by July.