if you want to know how “mature” these emulators are, look for a mupen or reicast emulation on NVIDIA SHIELD with tegra processorat youtube . really smooth gameplay!
psx higher resolution is smooth now!
Dreamcast is a “near playable”, but still too slow to enjoy on Rpi3.
N64 is still messy/bad on Rpi3… i bought pi3 causei wanted to play goldeneye but its still too bad to play…
We have to wait till we have 64bit to hit the real performance…