I don't mind Support but I hate to Jungle because it is the position with the highest pressure.
Most people play what they know. However, imagine that your Top Laner is first pick and they pick Poppy which to which the enemy top responds by picking Darius Top. If the Jungler doesn't gank this lane constantly the Poppy will get pushed out of lane and then the (probably fed) Darius will roam on the other lanes.
Basically the Jungler's job has gone from "clear Jungle camps to keep team's overall gold high" to "gank lanes that have unfavorable match-ups". And that doesn't even usually work because you are either by yourself against a fed enemy or you are 1 v 2 against fed enemies.
Honestly, I just wish we could have the option of either Jungling or being a support for the Top Laner. I mean... Duo Top is usually the fallback if the Jungler forgets Smite anyway. So why not just pick a support champion (like Soraka) and go support the usually lonesome Top Laner.
Besides... If you do well as Top Support you and the Top Laner could go for Rift Hearld.
Hmmm... I think the next time I get filled Jungle I'll just go Top Support instead. :)