I did some research, and they look quite good, with bonus 1000%+ elemental+ normal damage. Conviction decreases enemy resistance by 95%. Plus, being able to max holy shield, giving way more points for vitality and also having 14 in all resist skills giving me 7+ extra resist in f/c/l. On top of that, I had the godliest gear: Crown of ages: Jah, Jah, Stormshield: Um, Enigma Dusk Shroud, Ethereal BOTD Beserker(around 600 max damage), Verndugos belt, Draaculs Grasp, Sandstorm Trek Boots, Carrion Wind, Natures Peace. All items perfect, except for BOTD which was around 380+%. My merc was defiance merc, with levatian armor, shako, and doom cryptic axe.

With all this I had max block, 2100(with sage), 4000-7000 damage(mostly elemental), 15000 defense, around 50/50/50/50 resists in hell. My merc survived almost better than me and he had: 2400 life, 40/40/40/40 resists in hell, 1000-2500 damage(mostly physical, some cold), 10000 defense.

I went to do hell meph, and I tell you, with 1 player in the game: ME, it took 2-3 hits to kill one of those fat guys(marduere) maybe, 2-3 hits to kill the bloodlords, 1 hit to kill the cadavers. Meph was almost as easy to kill as some of the monsters though. Vengeance is a slow azz skill, uses lots of mana, does crappy damage in the end. My pally died 2 times on way to meph. And if i faced the council they wouldve slaughtered me. Maybe max res would have helped but still look at my gear!

I am guessing that this is because of the monsters huge resists in hell, and I also think SP is harder than MP hell. But still, I reccommend you dont make this build, make a physical damage or magic build.