Haven't had too much of a chance to play with it properly other than checking it out connected with cable and connected via bluetooth. Feels comfortable in the hand, not dissimilar to the original switch pro controller but smaller. Dpad and analogue stick are pretty much placed in the same position as that controller too. The thing that I think will take the most time to get used to is the positive and negative points associated with it being so similar to modern controllers and therefore wanting to use the c buttons as the primary buttons rather than the a and b ones! Obviously these can be mapped and will make it easier to use for other purposes than N64 though which is good. All buttons feel nice, and the triggers are clicky without too much travel. Analogue stick feels good but obviously the gates will take a bit of getting used to after smooth travel on modern controllers.
Had some oddities with it connected directly to my steam deck via cable, almost like the controls were being sent in super fast pulses and then stopping (even analogue stick movements) but bluetooth seems ok. Also seemed OK on windows via cable. Seems like the kinda thing that might be addressed in a firmware update or was something I could tweak a setting for. Haven't tried the switch connection yet but apparently needs a firmware update to work with switch 2 (checked yesterday and it wasn't detected by the 8bitdo firmware tool despite some people on reddit saying they'd updated and it was working for them).
Only n64 game I've played was mario 64 on my retroid pocket 5 with rocknix over bluetooth. Needed to setup the mappings but worked fine and seemed responsive, easy to hit side jumps etc. c buttons mapped nicely and camera controls worked as I remembered. All in all, happy for the price and I'm sure that once I'm used to it, it'll be great for emulation.