I bought my VFD/spindle from CNC4YOU maybe 8-9 years ago and it's now fitted to its second router. Ran fine straight out of the box although I ended up making one minor configuration change to the VFD. It was something like being set to 4-pole and it was 2-pole motor (or vice versa). Made no difference to how it worked but the speed display was out by a factor of 2. I expect they've fixed that by now!

At that time, Chinese eBay suppliers were a bit more of an unknown quantity so I paid a bit more for a UK supplier. It's different now, but given how it's lasted I can't say I'm unhappy.