The latest generation controllers I have built all use the same simple and cheap IC's. A pic 12c508 as the basic stepper driver logic and some H-Bridge chips that were originally meant for mundane things like tray loading motors on dvd players. I got a couple of hundred of these on ebay. The pic micros were from a guy that used to do mod chips with them but sold out his stock of unused chips really cheap.
I've used the cheapest parts I could find and still got great results with modest fine tuning. I used a dial indicator to see how bad my table was and it only varied .008 inches in depth from end to end. If I had used a surface planed board or aluminum plate that would have been better. I could always just mill a huge squared spiral pattern into the table to make it perfect
Step 1: Single Board or Multiple Board Modules
I've tried both ways and each has its advantages. I always keep the 110V SSR board separate. When using the single board approach I like to use an Arduino nano clone. when using multiple boards I use and arduino prototype sheild wired with a bunch of headers for the individual boards.