Bridgeport Manual to CNC conversion...

[JAZZCNC]

Question is - is the benefit of real-time position DRO worth the extra cash?

Yes IMO but with the Cslabs controller there's more to it than just this. You also have very accurate Homing using the Index pulse of the Encoder. You can also Fit a Servo to the Spindle and control that just like an axis so can index to position or do things like ridged tapping etc.

Then you have 24V I/O etc not to mention you don't need a BOB. This Alone is BIG Plus, esp when using servo's. Don't confuse the IP-S with ESS they are completely differant animals.
While they seem expensive they are not actually that bad when you consider that it's one complete unit nothing else is required. It's also Industrial spec and high quality.
By the Time you have Bought ESS and Decent quality BOB like PMDX126, which about the only one I'd use with servo's plus Spindle speed Control board then your not long way behind the IP-S or IP-A.
They really do not compare other than both use Ethernet and provide 4Mhz after that it's all down hill for the ESS.!!

The motors I was looking at are from the same guy as in your video, drives the same too.

Think you'll find 750W will be most likely be 80 frame(like Nema34) not 110 which will probably be better for you. Drives may be smaller too.?