Current Jungle Rengar

So I've been seeing more and more pro players, LCS and challenger solo Q, opting for the full tank Rengar in the jungle over assassin or even bruiser.

I as well have stopped playing assassin Rengar in the jungle cause you seem to fall behind in levels no matter how fed you get making it extremely risky, so I've been building like hybrid/fighter/bruiser when jungling. The issue I've been having though is that if you do not get ahead early you have this like slump of ineffectiveness until you either get full built with loads of damage OR you get those first couple tank items and are beefy enough to survive in the enemies back line.

The reason I'm so trepidatious about working on playing more tankgar is cause since the W nerfs back mid season 4 building him that way just feels so underwhelming. Sure you can dive a back line and your damage is still rather high so you're still a threat to that has to be dealt with, but if your team isn't competent like they usually are then relying on them to focus the right targets and get out their damage in teamfights just leads to my death a lot of the time. Where as when playing more bursty you can blow up splitpushers and separate people from teamfights, as long as you're not cc'd at all ofc.

So I'm just curious as to the general consensus on these different build paths, is tankgar simply more reliable in solo Q since you fall behind in gold and xp in the jungle no matter what or is he too hard to carry with when compared to damage Rengar?