EDIT: i know one thing tho.. alot of people are hyping Ruin.. but tbh it aint that good (but then again.. huge insane wtfomgzCrits are fun to get.. its just that it never happens)
Edit2: found some math
Use a damage per second of cast time measure, to determine if a spell is worth casting.
True casting time = cast time + ((mana cost)/(lifetap mana))*1.5
Corruption (MD/ruin) = 2 + 340/420*1.5= 3.21 seconds.
Damage per second of cast time = 666/3.21 = 207.47
Shadowbolt (MD/ruin) = 2.5 + 380/420*1.5= 3.86
Damage per second of cast time = 481/3.86 = 124.6 dps.
Corruption (Soul-link) = 1.5 + 340/504= 2.51
damage per second of cast time = 666/2.51 = 265.34
Shadowbolt (soul-link)= 2.5 + 380/504*1.5 = 3.63
damage per second of cast time = 481*1.03/3.63 = 136.48 dps.
Crit % when shadowbolt spam dps is equal
124.6*(1.05+x) = 136.48*(1+x*0.5)
0.9586 + 0.913x = 1 + x/2
0.413x = 0.0414
x = 10.0%
Therefore, MD/ruin overtakes 9/31/11 for shadow bolt spam, when the crit% of both builds is 10%, without talents being included. (this is the equal gear assumption.)
However, when the use of corruption and/or curse of doom is included into the casting sequence, 9/31/11 pulls ahead, and stays ahead until the pre-talent crit rate of both specs is > 65%.
