This is pretty simple to answer.
None!
The only thing there good for is turn ins at the library.
Reason:
Scrappers. Most people will use a basic scrappers over any spellbook due to the LMC/SDI and casting bonuses. Add the fact that there are many +skill scrappers around...poor normal books
Invasion books(1). 30%sdi(best around) fcr2 (best) 10DCI(best) 5 LMC (not best but added with the rest)
Invasion books(2). 30%sdi, 10%lrc (not best but who really cares) mr3 (best)
Clannins book(library). 80luck(nice) Mr3(best) LRC 15%(best)
Clannins book(event). Forget mods but it basically adds all of the above in elsser extents.
Conjurers Grimoire(as tome of lost knowledge+ undead slayer). Magery +15, SDI 25%, think theres more i forget.
There are probably more arty books you can have. So, a crafted book can have 3 if the below combos:
SDI 12% (low)
Mr2 (nice)
Lmc think its 8 maybe 5
Lrc 15%
FC 1
FCR 2
Slayer
+skill (up to 15)
and i think thats it.
Now, take scroll consumption against actual odds of hitting something comparable to any of the arty books...and its really not worth the time. Might as well make recalls/teleport/res/wall of stone scrolls, sell them and buy greds fro a scrappers. At least its guaranteed a decent SDI book.