Yeah I got one and it's pretty sweet. Hits solid, runs smooth. I'd guesstimate a 4.2mm stroke.
As for maintenance, They glue/thread lock the shit outta the thing, so a real bitch to disassemble.
Wrap the hell outta the colored part and middle body with masking tape and visegrips did it for me.
If you're ballsy you could warm it with a flame to soften the locktite.