This is by no means mean to be a review of either grinder, both examples are used. The Grindermaster is refurbished and re-branded. I just though I'd share my comparison.

I've been using refurbished Grindmaster 850 for four of five years. I bought it for $70 from a defunct market which wasn't around very long.

This weekend I relieved someone on craigslist of their Super Jolly, the only catch was that it came with a bonus Bunn G1. The Bunn had an unknown number lbs run through it, so I decided to do a grind comparison. I have no use for two 50lb bulk grinders, and I can sell either and make up the cost of the Mazzer. So, which to keep?

Full Image: http://i.imgur.com/cMgXpqZ.jpg
You can really see in the full image, the Bunn produces more fines, and the coarse grind is less consistent. I'll chalk this up to worn burrs. I was hoping to keep the Bunn, I like the grind trap which reduces static... plus it's red, but it looks like I'll keep the Grindmaster.

Try to brew from each simultaneously and taste blind, see if you can tell a difference. Ideally, you'll have a control (e.g. total three cups, two of the same). This is a great way to remove any prejudices. And do the test several times over the coarse of a few days, see if your results are consistent, too.

Depends how you brew I guess. The Grindmaster is turning out a nicer coarse grind but the medium (Drip?) & fine grind of the Bunn looks better (fluffier) to me.