I main a plant/psi/ice but team quite regularly with a mind/fire/ice. As Tex said, they are very different.
Plant kinda relies on the enemies doing the heavy lifting and regen'ing yourself out of any problems that spring up. Chaos and smash. More AoE than ST but you can defo make-do. If you miss on the seeds cone and vines isn't recharged then you can sometimes get yourself into a hole, but shockwave with dom acts as another control. Dip between melee and ranged, I'm soft on s/l with a fair amount in ranged but cant remember the exact amount off the top of my head.
I always forget how annoying it is when the seeds dont work on the khels in ITF, so I sometimes get a bit of a hiccup there. And the psi-robot-resistance thing has been written about at length. But procs and the ice powers can help there.
Mind has a few more control powers which are useful if something else gets aggroed and things start going pear-shaped, with fire taking them down one-by-one. You'll be able to solo TFs for sure, dont know about the GMs. The Mind/Fire I play with likes to show-off that he can confuse the big crystal in the Eden trial, while I waft seeds and get killed. Feels more at home ranged it seems.
Try both, they're very fun.