I have the WJ200-022SF Hitachi VFD, purchased here: WJ200-022SF 3HP 2.2kW 230V Single Phase Input VFD - Hitachi
For setting it up with the 1F, refer to this post: Hitachi VFD Connection
I decided on an air-cooled 2.2kw spindle (no plumbing!) and I’ve been happy with the setup. I purchased the spindle here: High-Torque Stepper Motor, Stepper Motor, Driver, Stepper Motor kit, DC Servo Motor, DC Servo Motor kit, Stepper Motor Power Supply, CNC Router, Spindle, and other Components. (mainly to buy from a USA storefront).
I got a quote on the Mechatron, but couldn’t justify that big of a price jump for hobbyist use. If I was running 8x5 (or longer) every week I might choose differently.
If you want to go down to 3K spindle speed, I’d recommend looking for a 4-pole spindle that is designed for metalworking - they are wired to keep their torque at lower speeds, but don’t have the same upper-speed range.
Good luck!