Hi Christine88:
Regarding plug-in's for Mach3, the task is quite formidable. I am not a plug-in programmer, but do have a Pokeys and a UC300 for my small CNC project mills.
Reading the plug-in history for the UC300, it was a long and difficult process to achieve the current state of reliability, and the plug-in's for the UC100, and the UC300 are different plugins. Both of those USB units are now very reliable, and also have a completely automatic installation process over the internet, which is pretty slick.
The same time consuming process was the Pokeys development.
I am building a plasma installation for a customer, and am using the Ethernet Smooth Stepper board by Warp 9. They still do not have an automated installation, and there is a lot of fiddling to do, getting all the pieces to work. However, it is said by many on this forum, to be an excellent product. Since starting this ESS build process, there have been 2 newer plugin versions for the board.
All of these above mentioned boards are fully Mach3 compatible, and the ESS is nearly complete with the Mach4 plug-in.
Just a little trivia i.e. plugins.
John