Hey Remik,
Some U.S. users in this forum are running Hitachi WJ200 and Hitachi S1 which were available in the U.S., these are models which Mechatron offered with their spindles when Omron MX2 had a temporary availability problem. Hitachi WJ200 and Omron MX2 are practically identical.
Assuming you have U.S. 240 V single-phase from split-phase electricity and want a VFD for a 2.2 kW motor, the Hitachi WF200-0220SF (which is identical to Omron 3G3MX2-AB022-E, which Mechatron initially sold with their 2.2 kW spindle) costs $360 USD here in the U.S.
The ATO GK3000-2S0022 is available for $238.14 USD. That is indeed less than for a Hitachi or Omron. Haven’t heard of any experience with these VFDs. They ship for free, however if they ship from China you will have to pay customs fees.
Besides the specs overview on the item page, I cannot find any documentation for the “ATO” VFDs. Do you have access to a manual of these VFDs, like the Omron MX2 Manual or the Hitachi WJ200 Manual?
I just had a look at what you pay for the Invertek Optidrive E3 2.2 kW here, (which is not made in China, but in the UK(!)): I pay € 283,71 here: Invertek ODE-3-220105-1F42. That’s a good price for a VFD with Sensorless Vector Control that is not made in China!
A VFD made in UK – would look good next to my computer and controller made in Germany.