Mike,
I make knives as a hobby. I'm on no schedule. My livelihood doesn't depend upon it. I'm not prolific about it. I do it because of the pleasure I get from it. My perspective of knifemaking follows those lines.
That said, let me address your points:
You get the grizzly, and when you find out how limited it is, then come on back and tell us all about it.
I wouldn't have addressed the tooling arm question if I had not used a Grizzly beforehand. I feel it bad form to talk knowledgeably about a tool if I haven't used it. I own a Grizzly. I use a Grizzly. I know, first hand, that it will track belts accurately and smoothly on wheel or platen. Mine has been reliable in 5 years of use. Those qualities fulfill my needs; as nice as they would be to have, I feel no need for a top of the line machine.
Of course you can change wheels on it, that's not what I was talking about as far as upgrades. That's just normal toolling change out that any grinder has.
Sure any capable grinder can do that, thanks for clarifying what you meant.
Can you make it variable speed if you choose? Can you change out the motor at all as a matter of fact? No you can't!
I have to disagree. It's not as simple a task as it appears to be on other machines, but it's not that difficult to do.
http://groups.msn.com/GrizzlyG1015/myg1015modifications.msnw?action=ShowPhoto&PhotoID=54
http://groups.msn.com/GrizzlyG1015/recondocsgrizzlymodification.msnw?action=ShowPhoto&PhotoID=68
http://groups.msn.com/GrizzlyG1015/brettbennettsmodifiedgrizzly.msnw?action=ShowPhoto&PhotoID=72
I have never said that the Grizzly was a perfect machine. It needs to be tweaked out of the box (so did my 1911

I know, not the same thing). It runs fast in stock form (but, slower than the stock specs. for a Square wheel). The platen isn't the best. Hollow grinding on the 8" wheel is not the easiest task to accomplish. A pro's machine? No, but I still believe it's a capable machine of good dollar value.
Mike, I would be interested in hearing what problems you encountered using a Grizzly.
Have fun whatever your choice in tools
Regards,
Greg