I’ve been trying to figure out the probability that you’ll get a higher level item out of the grinder. It’s obviously easier to find white and green items to grind, so there are more of those in the stats than blue and purple. If you want to contribute data, just post in the thread below, indicating at least the initial rarity and the number of increased rarity to total grinds.
I’ve split the data out to take into account the recent patch that increased legendary drop rates. First table is data with the new rates, while the one below is the combined data from before the patch (and before the drop rates experiment.) I’ve also included the data from @decimus28umo.
Running totals for non-moonstone grinds, post-patch
|Type||Increased rarity||Total grinds||Success rate|
Note 2: So far, three glitch or three orange rarity items always seem to give you the same rarity back; the numbers on these are pretty low still though (39/39). This seems comparable to three orange items.
Running totals for non-moonstone grinds pre-patch, including data from @BuddyPharaoh and @Lance_Chaser:
White: 273 / 344 = 79.4% success rate
Green: 246 / 409 = 60.1% success rate
Blue: 72 / 164 = 43.9% success rate
Purple: 7 / 133 = 5.3% success rate
Note 1: I’m fairly confident at this stage that it makes no real difference to the rarity of the item produced whether you use three of a kind, or two+one, or even three different items.