From:
http://blue.cardplace.com/newcache/en/166546791.htm
Feral weapon skill is a lot better than a lot of people think. Assuming the blue post is correct, 1 FWS gives the following against a +3 lvl mob:
+0.2% hit
+0.2% crit
-0.1% chance to be dodged
-0.6% chance to be parried
That may seem like a lot, but Kalgan has said WS is the "'best stat' you can get against a target 3 levels or higher than you",
http://forums.worldofwarcraft.com/th...207273&sid=1#1
So the Lower City ring with 20 FWS
rating would give you 5 FWS resulting in: + 1 hit, + 1 crit, -1 mob_dodge, -3 mob_parry. -Mob_parry should only come up while tanking, and I'm not sure how the -mob_dodge works, but at the minimum you could consider 1 FWS rating = .8 hit rating + 1.1 crit rating for item comparison purposes.
I plugged your stats into Emmerald's spreadsheet and with the FWS rating conversion:
Shapeshifter's Signet = 111.4 Kity points
Band of Ursol =83.9