The cheap plastic HF grinder is a POS. I used to think it was OK for occasional use, but I've handled a few since then and they are not very sturdy. I *might* use it for depth gauges, but it is so damned flexy that I cannot imagine it producing consistent results even in that role.
The $99 NT grinder is the way to go in a cheap grinder. Alternatively, the entry-level Oregon one ($150 or less) could work, too. It isn't as adjustable as the other grinders (no +10 degree tilt on the chain holder or provision to sharpen hedge trimmers, I believe), but for zero-degree flat-filed chisel or semi-chisel it would do the job.
MAXX grinders can be had from a couple sources. Most everybody I know got theirs from Jeff Sikkema directly or through his eBay store. Otherwise, your other choices in a reasonably priced grinder are the extremely similar Oregon 511A, Tecomec 136, and Bailey's SpeedSharp. Any of these grinders will work quite nicely; they only differ slightly in their method of adjustment and operation from that on the MAXX, and neither design is clearly superior to the other.
