Hi,
I have used an Ethernet SmoothStepper (Warp9TD) for six plus years, been great. It is a step/direction controller
so it WILL NOT support analog servos but WILL support any step/direction motor drive from steppers through servos.
I have bought three 750W B2 series Delta servos for my new build mill, and I run them up to 5000rpm with 1um (linear)
resolution which requires a Step signal rate of 416.7kHz, and the ESS does that easy.
US made, and has a manufacturers sponsored forum for support, has both Mach3 and Mach4 plugins.
Craig