Hi Mike,

Got your PM and I'll gladly advise.

The Cslabs controllers are great piece of Kit and thou expensive worth it IME. Chaz's needs where slightly different to yours how ever because he had DC servos with Drives that would only take Analog signals. So he bought the IP-A. Has it happened he ended up replacing motors/drive with AC servos that would take Step & Dir signals so could have used the IP-S. That said Modern AC servo's also take Analog signals so he could use the IP-A controller anyway. Infact the IP-A controller is the better option because of the abilty to close the Loop all the way back to the Controller rather than just between drive/motor.
This means the Control software knows where the machine is at all times. So if for instance you push the Table while control software isn't in charge it still knows the exact location of the tool in relation to the table at all times because of the Encoder feedback to the Controller.
So In affect you only need to HOME at the beginning of each Session and untill power is removed the Control knows where it is at all times effectively meaning you don't need to HOME after every E-stop or control Reset.

Now with normal Steppers you haven't got this option because you don't use Encoders. Also most Stepper drives only take Step & Dir signals and the IP-S Doesn't take Encoder feed back only the IP-A does and this can't produce Step & Dir signals.
So you have either the IP-S or the IP-M to choose from. Now with Steppers the IP-S is really way Overkill because you don't need all the Mhz pulses it can provide. In performance terms it would be like running NASCAR in First gear all the time.
However it does have some features the Lower Spec IP-M doesn't that would really be useful to Mill owner, like Backlash Comp and more I/O capabiltys.
That said backlash Comp isn't very good on any machine and your better spending money to remove the mechanical backlash than relying on software to remove it. In which case I wouldn't buy the IP-S just for this reason.

The IP-M is more than capable of running steppers to there Max with overhead to spare so in performance terms easy does handles the job.
In I/O terms it's got less to start with and can't be increased using the I/O module like the IP-S/A can. (Or it couldn't but that may have changed with software updates.?)
But it still comes with resonable amount anyway so provided it meets all your I/O needs then for a 3 or 4 axis Mill using steppers the IP-M would be my suggestion.

You still get all the great bennifit of Industrial quality controller with 24V general I/O. Analog I/O and Spindle Speed Control but at half the price. Software is excellent with frequent Firmware updates released. Support is good thou can be slightly slow to respond but when they do often resolve your issues. (which are often your issues not the controller or software.!!)
If your thinking to use Servos then Go with the IP-S or IP-A because you'll need the higher pulse rate they offer. Same if you need lots of I/O because you'll be able to use I/O modules for pretty much unlimited I/O.

Now the Other Controllers like ESS and Pokeys are very capable Controllers but they have what I consider BIG draw back in that they use Breakout board for I/O connection and use 5v logic signals which is prone to noise issues and can lead to all sorts of other head banging sessions.
The Only Breakout board I'd consider using with either of these controllers and Esp the ESS is PMDX 126. Now for us over here in UK or EU the price of importing the ESS and PMDX from States makes the combination more expensive than the IP-M.

For you then this combination is probably the cheaper option. It does give higher pulse rates than the IP-M and slightly more I/O but not 24V thou the PMDX allows for using 24V Prox switches.
In terms of quality and Software/support then nothing comes close to the Cslabs in this price range.

Pokeys is Ok but doesn't come close to IP-M or ESS/PMDX.

CncDrives UC300 is ok controller but USB connection lets it down and it still use 5v logic. Ethernet is much more robust.

Hope this helps on the controller decision.

Drives then I'd say go with Leadshine Digital drives EM806 or AM882. Even thou you live in Gecko territory the Leadshine is better drive IMO.