What tank should I buy for top lane for 1350?
What is the best tank ATM?
What is the best tank ATM?
Morde isn't a tank.
Rammus is a better jungler.
Mundo is more of "tanky", not a true tank (pick him if you want to deal damage while being tanky).
Sion is a bit weak right now, but is getting buffs next patch.
Malphite is best against high AD teams, or playing with teams that synergize with his ult for a wombo.
Cho'Gath is arguably the overall strongest out of that list
Later model Panzer IV is always a safe bet. Good balance between mobility, armor and firepower.
Just get
for 450. Since she is picked for her utility more than anything else she will fit most compositions and will have a decent time with more common laners.
is currently quite strong but is drawing attention to itself, expect nerfs not so far in the future.
and
are decent but there are not really for the current meta, they have awkward playstyles and won't fit well with random players.
are a tad too weak atm, they can be successful on specific niche and against certain match ups, they are good for pocket picks but not so much for spamming them.
If I were you, I would save up for one of the more fun top laners. Gnar, Jayce, Fiora, Rumble, Jarvan, or Maokai.
is banned alot
has buffs coming soon, he is already a decent pick... he does have a learning curve
but if you ask me ...

http://current.lolalytics.com/champions/
http://current.lolalytics.com/champion/Maokai/Top/
Maokai Top has a win rate 53.48% for Platinum+ players whilst the very best Maokai's are earning a win rate of 60.06% with the average rank of these top players being in Diamond IV.
LoLalytics ranks Maokai at 1 amongst Top champions earning a tier grade of Challenger.
This ranking takes into account the win rate of Platinum+ players, the pick/ban influence of Maokai, the win rate and average rank of the best Maokai players.
Hello. I count as a tank now so you can add me onto the list :)