Hi @PhilB,
Thanks for the quick reply. I really like open source and really like to have things run the way I want them to. Also get tired of things happening or usually not happening with vendors. The latest is that Mach4 V2 may not be compatible with PoKey57CNC. Previously I waited for upgrades to the awesome Gecko G100 drive controller and Mach3 that were supposed to support threading. It never happened and later after I smoked it found they had discontinued it so I switched to the PoKey.
My set-up is probably on the high end, for DIY. Its a Shoptask Mill/Lathe I converted to CNC with junk parts or e-bay specials. Thats why the 2024 lpi encoders instead of something more reasonable.
Back to the questions.
1. Thought I'd read that your optical encoders were only good for 25kHz, the 160kHz sounds great.
2. Had to learn LUA language to get Mach4/Pokey to basically do an E-stop, save some data and dereference the axis. Not to bad, but how many languages does a person have to know to play with CNC
3. Playing for years with Teensy 3.2, 3.5, 3.6 and now 4.1 I have all kinds of inexpensive sensors and displays, all on SPI. Its just what works best for wired sensors with cables around 6ft. I2C stuff tends to be on the board and still fidgety.
4. I'll have to look at this stuff.
Why would I want to switch

... Because its there

Half the stuff I've made is for the milling machine itself, although in the last few years my attention has switched to a Prusa 3D printer with half the stuff I make for it!

. Now I design and refine with plastic on the Prusa, then go to the CNC for final parts.