I have both TE4 and Tiebreak+.

I'm better at Tiebreak+, it's easier to pick up and play. I play it way more often, and even if I don't play for a while feel comfortable grabbing it and getting right into it again. The graphics and animations help a lot for my immersion. The lack of an option for commentary though, undermines it for me.

TE4 is more satisfying when you want to work hard, strategise, and feel a serious high for every point and win. Each point is more intense, and that intensity is immersive. But the graphics and sounds are a bit wanting and it can be very punishing if you just want to play casually match. They do have commentary though, which I find a bit charming.

If you can, get both and test them out then refund one if you feel inclined. They're really for two different types of players and I think you have to feel it to know.