MF on a Sorc, how much can you call worthy?

[Master Q]

Hi guys :azn: I was wondering: I got my 91 sorc doing well her Baal run and I can achieve 422% mf on finishing strike for him. I could raise it more if I would wear two Nagelrings nearly perfect (both 29%) say reaching about 500%, by slowing down a bit my killing speed (substituting a Bul-Kathos & a SoJ increasing my dmg). Question is: is 60% mf worth -2 to all skills (consider I actually own the bastard pretty quickly, 5 mins from the waypoint on) or is it a mf increase that won't make that much difference?

[Darkflight]

Going from 422% to 500 % MF is not worth it if you loose killing speed. If the killing speed stays the same and your safety doesn't decrease you might as well go for it.

In this case I would not suggest it since I think +2 skills will increase your killing speed somewhat.

[BlackWinterDay]

True Unique MF @ 422 Total MF= 157%
(422 * 250) / (422 + 250)
105,500 / 672
156.99

True Unique MF @ 500 Total MF = 167%
(500 * 250) / (500 + 250)
125,000 / 750
166.67

Not worth it if you lose killing speed, imo.