Hey all,
the Hitachi WJ200 is nearly identical to Omron MX2, see here.
I recommend it highly over Huanyang or other cheap VFDs, see here.
By the way it’s these VFDs that Mechatron uses in their Control Cabinets or that they sell in their spindle/VFD bundles
Further Reading
“Omron MX2” on Onefinitycnc Forum
“Hitachi WJ200” on Onefinitycnc Forum