Previous PCBs I've designed using EasyEDA have used a 100mil based grid with 25mil snap and it works fine.  However current PCB is all SMD so I'm using a 1mm grid with a 0.5mm smap.  This usually works but sometimes, especially when moving vias, the via offsets left or right a little and it takes several attempts to get it in the correct place, usually involving zooming in a lot. Also when moving components I often find them centred on xx.04 mm or xx.96 mm, which suggests something is possibly still working in mils.  Only way to fix this once they are wrong seems to be to type in the correct co-ordinates in the right hand side window.