Well, here's the pros and cons for Androids vs Ipad/Iphone vs Emulators for Ensemble Stars!!:
Android:
Pros - Easier to buy diamonds via G-Pay and Paypal through the app, cheaper products to buy overall, can easily update the game through QuoApp without hassle
Cons - Samsung products are garbage for the game because touchscreen issues, sometimes won't load models for MVs (meaning you often get lag in game if you're not using 2D/basic backgrounds only)
Apple Products:
Pros - Usually runs better/less lag (improves actually playing the game)
Cons - It's a pain in the ass if you live outside of Japan to actually buy diamonds in the game (you have to use VPN and set up a Japanese itunes . PLUS you have to only buy using Japanese itunes giftcards), products themselves are expensive because of better specs, there have been reports of models in the MVs tending to be more buggy on Ipads but it doesnt necessarily cause lag (which just means it's funny how the models in the game act)
Emulator:
Pros - You can adjust your specs to basically get the benefits of either Apple or Android with just better graphics and memory, less lag in general (depending on which emulator you use, Nox tends to work better but I played on Bluestacks originally and it was fine), autoclickers can be used for the visual novel sections of the game to farm diamonds easier
Cons - HappyElements (the developer of the game) will ban you if they find out you're using an emulator even if you're using touchscreen (they strictly enforce the no emulators rule for the rhythm game version more than the original version of the game though; I still use emulator for Basic since it's easier to play on emulator), autoclickers are a risky choice because you could get banned for using that too (even not using it for the rhythm game itself but for the VN sections)
That's basically a summary of what the community has told me vs my experience with the game. I use a Samsung and get touch screen freezes but I still can maps and FC if I'm patient enough to just restart the app and try again.
I highly recommend Ensemble Stars!!, more for the story and lore though. Gameplay can get stale if you're not actually reading the translations to the VN sections of the game. The best part of the game is getting to know the characters.