Motion Controllers - Chinese

Hey!

First post here.

I am a software developer, and if you'd see the little work bench I built myself, you would have no doubts about it. But, it does the job, though!

So I got myself a china CNC router "6040" thingy, one with 3 axes, ball screws, and VFD control inside the box.
I.e., if I'm bad at precisely building things by hand, I guess, a computer should make it for me!
Sound plan, eh? (yes yes, I know it's not as easy, I have to learn about proper tools and feed rates etc )

I do know (roughly) about their limitations and am expecting at best to work with a few millimeter thick aluminium sheets (DIY musical gear front panel cutouts and such), mostly plastic and wood parts milling, and PCB milling.

As I understand, the printer port control scheme of those CNC machines is a bit "too direct" to work reliably with a program like Mach3 running on windows, as it's not real-time.
While I will try LinuxCNC and already have put together a (not too) old PC (which currently refuses to properly boot from LinuxCNC dvd but installs winXP just fine),
if the level of frustration that presents seems too unreasonable at some point, I'd certainly also look at other routes.


One such is, from what I got, to get a motion controller box/board, either one that connects to the printer port connector of the China CNC controller box, or one board for internal mounting (in the control box, replacing the printer connector board).


Those here motion controllers are stocked in my country (Germany), so I'd prefer them because 1) in case they need to return, I could send to a national address instead over seas, and 2) of course because it's here in a matter of 2..3 days, instead of months.
Very different price ranges, and probably features:

(I cannot URL those links with < 10 posts, sorry for the inconvenience. I used short links for easy copy & paste )

CNC-USB-Card-MACH3-100Khz-Breakout-Board-4-Axis-Driver-Motion-Controller
ebay.de/itm/122831187103

MACH3-4-Axis-100Khz-CNC-USB-Breakout-Board-Interface-Driver-Motion-Controller
ebay.de/itm/123025911824

RTM200-USB-to-LPT-adapter-200KHZ-USB-CNC-Motion-Controller-for-Mach3
ebay.de/itm/162994757907

200KHz-5-Axis-NVUM-CNC-Controller-USB-Mach3-Motion-Control-Card-Board
ebay.de/itm/112914061217

2018-NVUM-NVEM-CNC-Controller-3-4-5-6-Axis-MACH3-Ethernet-Interface-Board-Card-2
ebay.de/itm/112889334336

Fancy stand-alone thing:
ebay.de/itm/122939418382
NEW-DDCSV2-1-500KHz-CNC-4-Axis-Motion-Controller-G-Code-Stepper-Motor-Driver


Are any of those any good?
I already heard the Novusun has bugs AND support issues, probably its clones are worse. Did look tempting b/c network support instead of just USB... that would be very neat, but not strictly required.

I guess they'd better not have too crappy algorithms to transform G-Code into a milled result, right?
Anyone know anything about those boxes and their important properties?

How important is the PWM frequency a controller supports (assuming it does not exceed the maximum the motors are specified at)?
There are some as low as 50 kHz, then I think my CNC came with steppers said to work at 200 kHz, and then I have seen some controllers working at 400 or even 500 kHz.
Are they just working at those, or is it their maximum and it's compatible with motors which can stomach less?

Have a nice weekend
(we finally got spring here in Germany!)