On one hand you have entire arsenal of death spells that remove mosth of alive things with one click, undeads are really strong and with SR in 28-30 range they ignore turning, scrolls and low level spells from non-clerics, extended blackfire is wizard's hell inferno. All of it is really nice.
However it comes with a drawback of no premonition, no see invisibility, no true sight, all three are very useful because on lvl30 everyone have those and you cant even read scrolls and need to rely on staffs. Which is not a problem in pve scenarios (but even then theres invisible enemies) but pvp - in wide sence not only just combat scenarios - lack of TS and SI really hurt you.
You have problem with death immune enemies, saves on death spells are not very high so most of the PCs - and many npcs around lvl30 dungeons - can pass those relatively easily, so you hit them with circle and then banshee and half of them still standing.
Also Spe.Necr pretty much guarantees a death aura and the moment people see it they assume you're a pm/necromancer (even if death aura does not nessesarily means that).
So yeah, its mixed experience and you should be ready you'll have serious drawbacks.