The best spoke key is the one that fits the nipples you're using. The green / black /blue / red Park ones are fine, the circular plastic Spokey one is fine. Just get the right size.
I have the three-size metal Park one as well and it's not very nice to use, to be honest. It's fiddly because you constantly have to search for the right sized slot. Maybe ok just to tweak a few spokes but if you're building a whole wheel it gets a bit irritating.
The best spoke key is the one that fits the nipples you're using. The green / black /blue / red Park ones are fine, the circular plastic Spokey one is fine. Just get the right size.
I have the three-size metal Park one as well and it's not very nice to use, to be honest. It's fiddly because you constantly have to search for the right sized slot. Maybe ok just to tweak a few spokes but if you're building a whole wheel it gets a bit irritating.