Xin Zhao or Tryndamere
I have been jungling lately and really want to buy a 1350 ip jungler. Which one is better when it comes to sustain, teamfighting, damage and who is more tanky.
I have been jungling lately and really want to buy a 1350 ip jungler. Which one is better when it comes to sustain, teamfighting, damage and who is more tanky.
hands down. He has CC on his Q and ult plus a great debuff. That makes him much more valuable in teamfights. They are pretty even on everything else.
Trynd is not a jungler
uhmm Xin? Because Trynd is basically known for being a toxic split pusher.
Tryndamere
Xin Zhao for the points you made.
Tryndamere does not know teamfights.
is worthless go with 
xin, he's more versatile for one (can build devourer, warrior or cinderhulk, they're all valid on him). His early game damage is stuuuupid even without items, or if you build full tank. he can be a primary initiate or a carry killer depending on how you build him. and he knows that to be a man you must have all the strength of a raging fire, and to be as mysterious as the dark side of the moon.
Both are insanely broken (NOT overpowered or underpowered, but broken) and easy to play, but as a Jungler I would probably say Xin Zhao. He's solid and can fit into/against most team comps.
Typically Xin Zhao builds more tanky and has better teamfighting, but Tryndamere can do significantly more damage if he gets a lead.
I have been jungling lately and really want to buy a 1350 ip jungler. Which one is better when it comes to sustain, teamfighting, damage and who is more tanky.

Xin'Zhao ties Tryndamere or exceeds him in those catagories.
Most notably in team-fighting: Tryndamere's team-fight potential is pretty much the worst in the entire game.
Xin can also get away with building a lot more bulk, as his CC/utility can actually make him a pretty solid tank/innitiator.
Xin's damage is also better than Tryndamere's for most of the game, and if you go full AD adventures Xin - his ~3 AA steroids in AD, AS, and armor pen allow his late-game DPS to come pretty close to that of Tryndamere's hyper-carry damage. The important thing here though is that Xin's damage is unusually solid early game when you can actually force 1v1 fights and Tryndamere's is complete garbage until he gets items, and then when Trynd gets items nobody wants to 1v1 because they're grouping up.
Concerning jungling: Xin is a lot stronger, as his mix of sustain, early damage, and amazing CC allow him to clear and gank quite effectively. Tryndamere is more of the AFK farm jungler variant, which sacrifices a lot of early pressure for you team.