Dean has been very restrained in his comments about this machine! My own first CNC router was built from MDF to a widely-available design, and I was attracted to that by plenty of video clips and so on showing how well it worked. And it did work, and turned out some useful work. But I spent more time tweaking and adjusting and repairing and strengthening it than I actually did using it! If you go ahead with the C-Beam machine, regard it as a taster and not a real machine, and one that you will grow out of very quickly.

On the subject of controllers, you are looking at something which is rather OTT for the machine. Cheaper and functionally better solutions for a machine like this (and that would be still be very usable on a Mk2 machine when you build it!) are available. Undoubtedly the cheapest but very workable solution is to use LinuxCNC with a simple break-out board. You could pick up a suitable second-hand PC from eBay for around £50, find a cheap monitor/keyboard, breakout board from eBay for a tenner, and you're ready to go. You are going to have to buy stepper drivers and so on anyway, so I'm not including those.

That needs a machine with a parallel printer port. If you want to avoid using one of these (and you are unlikely to buy a new PC these days that has one) then the next-best is something like a UC100 controller which connects to the PC using USB. That will run with Mach3, or can use UCCNC software which is cheaper and is becoming fairly well-regarded. Add in a breakout board again, and assuming that you have a spare PC available then you have a decent motion control solution for around half the cost of the Centroid and which will transfer to a Mk2 router very nicely.

Just some thoughts. There are plenty of build logs on this site which show the range of machines that members have built, almost any of which will beat the C-Beam hands down! And there's plenty of help and advice available once you get started.