I'm jungling with her, starting with riposte - which is godlike for jungle - leveling it first, getting E second, and Q once on lv3. Her ganks are very deadly. Runes: armorpen(red)/armor(yellow)/cdr per lv(blue)/movement speed(quints)
Item build in order of buying)
armor+pots
boots
lantern
boots+3/merc threads
phage
inf edge/black cleaver
frozen mallet
black cleaver/inf edge
sell lantern -> bloodthirster

depending on enemy team i'll get either one of those:
banshee's veil if they have annoying as fuck spells or Last whisper(if they are more tanky with tons of armor)

this gives me a nice 2,8k hp, high ad and nice armor reduction(which is applied by ulti).

Her passive is better than you think, especially for jungle. it dosen't give that much sustain as WW's one but that is nice extra healing after you finish the camp of creeps. Also remember that it stacks up to 4 times when you hit champions which makes her great at 1v1(this tiny bit with lifesteal from lantern lets me survive 80% of times).

I think that building atk speed on her is a waste - with just black cleaver and using her E she has 2.050 atk speed, and at rank5 she can use it once per 3 seconds or so(it last 3s, then 3s cd after that)