Review on iPega PG-9087S Wireless 4.0 Game Controller Gamepad Joystick for Samsung Galaxy S10/S20/Note10, 🕹️ Oppo, VIVO, Xiaomi, LG, and Smart Android Mobile Phones & Tablets (Android 6.0 and Above) by Bim Cook

The input lag of this controller is very low for a Bluetooth input device. I tried it out on an Android device with Retroarch and mGBA, which already has a small amount of input lag by default, and this gamepad didn't add any noticeable extra lag, which is pretty impressive given how cool Bluetooth can be. The folks who developed this thing seem to understand that it's used for many Android emulators, so they made this thing's responsiveness top-notch. The reason it gets 4 stars instead of 5 is that it has many small but passable flaws. Some buttons are small. Processing quality could be better. Analog sticks are pretty basic. Bluetooth pairing can be tricky at times and needs to be reworked. It may also not be suitable for large phones when they are in a case. But in general there are worse Bluetooth gamepads out there than this thing that actually cost more money. For $30 (or $20 if you order direct from China if you don't mind the wait) it's a good buy.