Depends what you expect. On a pro tournament level, nobody will use a vertical mouse. Usually they are a little bit heavier than regular mouses, plus they have a slightly higher center of gravity. This makes them a little bit more “wobbly” during ultra fast movements.
However, for regular playing, they work just fine. I don’t play on pro level, but okay competitive shooters almost daily, and I haven’t noticed any real disadvantage. And it helped my wrists enormously, because I’m a full time office worker as well. I decided a couple years ago that the small theoretical disadvantage is not worth the risk of RSI and have been using the cheap CSL/Anker/whatever vertical mouses since. Only very recently I boughta second, regular mouse with more thumb buttons, useful for some sim games I play. I now tend to switch fairly randomly between the two, which probably is even better for hand and wrist.
Additional info: getting used to a vertical mouse takes much less time than most people expect. Yes, it’s weird at first, but start working or gaming and you’ll stop noticing the different posture very quickly.