Since Amumu is always banned in ranked.

I need a great new jungler for solo Q ranked

Maokai

OR

Skarner

& Why?

Maokai probably.. More difficult to kite, and his snare feeds your team kills.

Maokai is probably both safer and easier. Skarner has some of the same troubles Udyr does - if you can play the one well, you'll probably do ok with the other, but either way they're situational picks.

I'd also like to recommend Nocturne - I've been having alot of success with him recently, and he provides a better option the Maokai when your team needs damage.

well my two fav's are udyr and skarner, so i'd take skarner but like they said above - they're hard to use. nocturn is also good... never tried maokai to be honest.

don't be afraid to try blitz jungle out. his clear time isn't all that bad and his ganks are epic (if he doesn't happen to get insta-banned). ever try fiddle or shaco jungle? both fun

Of the options, Mao would be my suggestion. Mao is a bit more versatile, and I expect the team tank to be the jungler the majority of the time.

Mao can also be run in a lane if need be thanks to them saplings. I've just never seen anything with Skarner offering something special, aside from the teleport while ulting enemy champ bug.

I'm going to assume you already have played both some and have had some success with them and find them fun. Why limit yourself to one. Play them both and learn their situational strengths, the use that to pick whichever one best mixes with your team or counters thiers.

If you don't own them, and are going to purchase just one, I'm curious why you limited yourself to those two with all the options out there for jungling.

actually.... i wonder why no one's used skarner when we now have homeguard boots.... homeguard teleport GRAB! XD but in all seriousness, maokai would be a bit more balanced of a pick. but if skarner's team comp is good and skarner doesn't get starved out of blue early game, he can destroy enemy team, one by one.

Mao is better for getting your team ahead with early ganks but i think scarner has more potental of just manning up lategame if you cannot trust people in solo que to take advantage of putting them ahead

When taking into account its solo Que neither one in my opinion is an optimal pick. Mao is centered around team fights. Specifically countering aoe damage with his ulti and being able to initiate fights. But he can't really carry a game that well imo. He can help feed lanes with good ganks but of you can't rely on your term to follow you in your kinda screwed. Similar situation with skarner as well.

Tanks just can't carry very well. Which may end up being necessary. Mao provides better ganks early. But skarner is better at peeling enemies for your team and his ulti is nice if u can tail the opposing fed player.

I personally enjoy people who can carry later in the game by themselves and cam snowball to a pain in the ass for the enemy team.

If the team comp requires someone tanky i prefer olaf or lee sin. For carries in the jungle good options are noc and shaco. Shaco mainly due to his late game split pushing abilities- entire enemy team can come to stop you and you can still safely retreat

These are just my opinions though and Im no pro. Out of the two i like skarner best but he's blue reliant