So Rengar got kinda rebuffed, but I still find myself getting very low in the jungle. I runed for 19 flat armor and go 12/9/9, so I have armor and health from the defense tree. Despite this I still find myself chugging all 5 pots through the first clear of the jungle and am really vulnerable. On top of that, I feel like I get less gold in general from S3 jungle, and it's difficult for me to get to a point where I feel like I'm an asset to my team and won't die immediately once I jump in. I must be doing something wrong.

Any other jungle Rengar players have some advice they can share with me? How do you play him with his recent changes in the jungle? What items do you try to rush? What are your ganking and teamfight strats?

I run Rengar 21/9/0 with flat AD Quints, flat AD marks, flat armor seals, and either scaling MR or cooldown reduction Glyphs.

I start hunter's machete and 5 pots. With 2 other people and great assistance, you can start at Wolves and clear them before the blue buff even spawns. After grabbing blue buff, I go Wraith Camp, Golem Camp, and then Elder Lizard (This way, your smite will have cooldowned by the time you start fighting Lizard). If I'm feeling confident, I'll clear either Wolves/Wraiths one last time and then b.

I build the Madred's and return to another camp until I have 3/4 Ferocity stacks, where I'll then immediately look for an available gank. Rengar realies pretty strongly on the early kills, and you won't be even half as effective without them.

If you're having trouble ganking and the enemy team doesn't have much cc, grab Mobility boots right after you finish your lantern to help you sprint into lane faster. With Mobility boots and ghost, there is almost absolutely nothing they can do to stop you from charging into the lane, slapping them with a bola, roaring in their face, and either bursting them down with an Enhanced Q or rooting them to the ground for you and your ally(ies) to pick them apart.

If you're fed and are getting many assist/kills due to successful ganks and plays, pick up a bonetooth immediately; otherwise, rush a Cleaver for damage and some sustain.

My usual build usually looks like: Wriggle's, Mobility boots (with either Furor or Homeguard), Bonetooth, Black Cleaver, Infinity Edge, Frozen Mallet.

If the game drags out long enough, sell the Lantern, buy a SoTD, and proceed to dive and destroy the enemy carry with your 100% chance to crit for 250% damage.

Other situational items you might want: Maw of Malmortius (Always rush the hexdrinker if the enemy AP is fed and nuking everything. No exceptions.), Guardian Angel, Bloodthirster.

Make sure you gank whenever your ult is off CD.
Build to counter enemy comp. Armor, Mr, HP

Make sure you know how to manage your ferocity for those snares.