Southperry's own Thief Flaunting thread =D

On average, without Decent SE, for a DB, the damage increase for a critical ring on top of what you would have on average is 1.69% damage (1.5/1.475), with Decent SE, it goes up to 3.22% (1.6/1.55), and with actual SE it actually goes down to 3.07% (1.675/1.625)

If you were to get a % LUK Ring to replace it, the amount of % LUK, then the % LUK ring should beat the crit ring so long as you have under the following amounts of % LUK:

Ring	Base	DSE	SE
3%	77%
6%	254%	86%	95%
9%	431%	179%	193%
12%	608%	272%	290%
15%	785%	365%	388%
18%	962%	458%	485%
21%	1139%	551%	583%
24%	1316%	644%	680%
27%	1493%	737%	778%

The blank cells indicate situations in which the critical ring is always better.

 Math

Because of Shadow Meld, I assumed 100% Crit Rate, so the average crit damage bonus is just the average of min and max crit, which hold the following values:

	Min	Max	Max DSE	Max SE
Base	1.45	1.5	1.65	1.8
Ring	1.55	1.5	1.65	1.8

Without the DSE or SE, the 155% min crit from the ring is rounded down to 150%, so the averages are the following:

	Base	DSE	SE
Base	1.475	1.55	1.625
Ring	1.5	1.6	1.675

Then the damage increases are (Ring Avg)/(Base Avg), which yields 1.0169, 1.0322, 1.031.

Then to compare with a % LUK ring, we choose a % LUK, dx, set the ring's damage boost (defined as 1 + the % damage boost in decimal form) r equal to (x+dx)/x.
(x + dx)/x = r
x + dx = rx
dx = (r - 1)x
x = dx/(r - 1)

Then the current % LUK is equal to x - 1 in percent form, since the damage boost from % LUK is 1 more than your % LUK in decimal form.

While critical rings are very nice rings as they are, I'm pretty sure if you had the funding required to reach one of the milestones (i.e. After 272% LUK with Decent SE, the crit ring would beat a 12% LUK ring), you could afford to get the next % ring (following the previous example, a 15% LUK ring). However, I'm sure there also comes a point at which getting the next ring is unlikely, for example, you have 645% LUK (is that even possible?) with Decent SE, but it's improbable that you could get a 27% LUK ring, at which point, the crit ring would pretty much be your best option. (Note, that I completely forgot that a primary and two secondary lines of the same stat at Legendary would be 30%, and a perfect ring would be 36%).

For now, this is a moot point, given that there are not yet 4 readily available third tier potential rings, but it won't be that way for long. But then, given that Tempest, Pinnacle, and Unleashed rings are no longer obtainable, you gotta think eventually the supply on those will run out, especially pinnacle.

Ah, damn, I didn't realise how little the difference in damage would be, I figured it'd be way higher, but since rings with potential seem to becoming more and more common critical rings aren't as useful as they once were I guess. Thanks for the breakdown, I would've kept stressing about having lost a good item otherwise xD
Also, jesus @ 645% LUK .__. with like.. 30% LUK on every single item and 9% on a few items in bonus potential that actually is possible. That's insane >_<