There was a recent thread about that very grinder, which at the time was listed for $600, but seemed to mysteriously go up in price after the thread was started.
The motor is far less than ideal for a metal grinding machine, IMO, as it's very fast, and open framed. It's also pointing in the wrong direction, IMO, as the way he has them set up, you have to weave the belt in between the wheels to put each belt on.
I'd also question how well it tracks with its tensioning method, which looks like it could be quite awkward, especially with a higher bench where you'd have to reach up and over to press straight down on the compression spring. With a pneumatic cylinder/flow control setup, it could be decent, but that'd add to the cost and require some modifications.
Personally, I'd probably go with the Oregon Blade Maker chassis for around that price point.