Short answer: barring a few exceptions, they mostly don't compete without being nearly perfect. Even "just okay" ones can be amazing in patch though, or often right up to 1.09/1.10.
Long answer: design your ideal craft and see:
iLvl of crafts == cvl*0.66
PREFIX
Cruel, 201-300% damage, iLvl=51
Master's 151-250AR, 101-150%dmg, iLvl=56
Celestial 301-400AR vs demons, 201-300%dmg vs demons, iLvl=45
Divine 326-450AR vs undead, 276-350%dmg vs undead, iLvl=45
Fool's, 0.5dmg/lvl 16.5AR/lvl, iLvl=50
Screaming 0.75dmg/lvl, iLvl=50
Weird, 301-450 AR, iLvl=37
+2 skill tab for Barb, Pal (sword, mace, scepter only), necro (wand only), and sorc(orb,staff only), iLvl=40 *(+3 is listed as magic only in the txts)
+3 tabs might be possible (ilVl=60)
SUFFIX
of Alacrity, 20% IAS (all weapons), iLvl=25
of Quickness, 40% IAS (melee weapons), iLvl=46
4-9% LL and ML, iLvl=56 (for max amount)
of Evisceration, 41-63 max dmg, iLvl=45
of Performance, 9-14 min dmg, iLvl=48
of the Giant, 10-15 STR (melee only), iLvl=59 (55 for scepters/maces)
of Ages, indestructible, iLvl=50
of Damage Amplification, 5% ctc Lvl 1 amplify damage, iLvl=3
of Simplicity, -30% req, iLvl=25
Hammers and Maces only:
of the Tiger, 21-30 HP, iLvl=51
of the Tital, 16-20 STR, iLvl=58
pick 4 (max of 3 of any prefix or suffix, assuming that part is the same)(at least, I think I'm remembering right about this part)