[BanduraMaker]

Well, if you have the tool under control then you have it under control - you can't outperform perfection. I would expect step size to be limited by the motors, not the ARM. The display thing is an example of straw clutching. The only reason a display was even being discussed was because I, a non-CNC person,

Mpack, I think I see the problem now. I was pretty certain that you couldn't be as dense as you're coming across, it's simply that you're ignorant of the issues at hand. So instead of responding with snide remarks I'll give you a little education.

Controllers like Mach 3 and EMC2 have thousands of man hours into them because there's no such thing as perfect control of the tool, at least if you live in the real world. CNC controllers make compromises in the tool path, or not, for various reasons which wouldn't be obvious if you were completely ignorant of how CNC machines work. e.g. We who work in wood prefer to use "Constant Velocity" mode to keep the bit from burning the wood. This mode looks ahead into the code to look for changes in directions and will make adjustments to the trajectory to try to maintain velocity.

Implementing something that will perform coordinated motion from point A,B to point C,D to point E,F is trivial but, implementing something with CV mode and acceleration curves (and there's different types with different performance) and backlash compensation and screw mapping and, and, and, is another story.

I see absolutely no point in arguing the merits of a machine like this. It's a good idea, and not just because it was mine. If it does not appeal to you, use a normal PC. Nobody is going to stop you. What no one seems to mention is that everyone has different needs and wants.

This is very true.

Right now, you can buy an industrial controller starting at about $1,250 + Computer with WINCNC

Flashcut is apparently up there in terms of quality and performance for about the same price for software and signal generator. AFAIK, it doesn't have the customization options that Mach 3 Does though.

Other industrial applications go up in price from there.

Next we have Mach3 which is close to industrial controller level but not quite there yet and has bugs and performance issues (smoothness of cut, CV acceleration bug possible, trapezoidal acceleration vs. S-curves). It's a great value and has a ton of support for $150.

We also have EMC2 (which I have no experience with) but it apparently is neck in neck with Mach 3 as well at zero cost.

Finally, there are Arduino based controllers which I know absolutely nothing about. Judging from the websites I've looked at though, they only have pretty basic functionality but it's enough to control something like a makerbot without much difficulty. There's a kit I've found for $370 that includes stepper drivers on the makerbot site. It comes in at <$100 without the driver.

The question I think becomes where in the continuum do you want this project to lie?

Personally, having an embedded type controller with all the features of Mach (minus the bugs) with a high speed clock for smooth control and a display (touch screen?) for <$400 would be super cool. Especially if it could be customizable with macros etc.

A <$100 very basic controller isn't very interesting to me but hey, there's probably many who would be into it!