Pokemon Masters is Seriously Pay To Win
Normally, in a mobile game, you can grind like crazy to earn a currency you can use in the game, or you can take the short cut and buy it. Pokemon Masters takes a different approach, making the grinding currency (gems) having different purchasing power than the ones you pay for. Some sync partners require you to spend money to unlock them.
This is a huge deal breaker for Pokemon Masters, as the battle system completely revolves around having sync partners who have one pokemon you can use in battles.
And it won't be cheap, it costs around $35 to unlock 10 sync partners. You're easily reaching territory of buying a legitimate game on a console, like the Nintendo Switch, for that price, and getting a lot more.
For perspective, Pokemon Sword and Shield are coming out soon, and they'll cost $60 for each version of the game, and you'll only need one. The choice between 20 sync partners in Pokemon Masters or an entire Nintendo Switch game is pretty obvious to me at least.