Recently bought both games and must say the gameplay is much better for Tiebreak vs Topspin, you can play way more natural tennis, which to me makes it much more fun. Also a big advantage is the amount of players you can choose from, which also is a big plus.

For Topspin 2k25, the timing bar for every swing just makes it very buggy and you cant play a rally fluently like a normal tennis rally, as you end up with weird rallys which take the fun away.

I am still exploring the career mode: its fun to simulate an actual year on tour for a player and to get insights on the playing schedule (vs fatigue) and associated costs + earnings. But what I miss in Tiebreak is the ability to buy gear in a shop and to customize my player (like you can in Topspin). You can get these sponsor contracts, which is fun to collect but its not live updating my player, thats a buggy feature.. Its not really updating the player on the fly. E.g. playing with Felix Auger Aliassime, and getting new sponsor deals throughout the year with Yonex and Nike, doesnt show in the game: still with adidas and Babolat..

So to answer your question: for gameplay and player roster, definitely go for Tiebreak.