Not real fond of thorns myself. It works, but I've found it deals not as much toxic as I'd like and the animations are too slow for my taste. Actual performance is not shabby and it certainly has some decent slotting options.
Mind is wonderful.
"Hmm, I guess I'm not as omniscient as I thought" -Gavin Runeblade.
I can be found, outside of paragon city here.
Thank you everyone at Paragon and on Virtue. When the lights go out in November, you'll find me on Razor Bunny.
Thanks for the info! 
Still debating if I wanna stick with this build, or the generic Mind/Fire build.
I've just gotten an Earth/Thorns out of Praetoria recently, and I really like it.
I'm mostly play Scrappers and Brutes, but I have a WS, a D3, a troller and now a Dom.
/Thorn plays like a second cousin to Spines, at least to me. It's fun, and I stay on my toes playing it, watching as mob after helpless mob falls to my AoE might. 
I've never tried Mind, but someone just soloed MoLRSF on a Mind/Fire, so I'm sure it's a solid primary.
I have a 50 mind/thorns/mace dom myself. Compared to all my other doms I'd say it's the slowest in regard to leveling speed and influence earning while solo. On teams, the combo is really strong at protecting the group. But it's not going to speed up the defeats that much and in fact you'll find youself mid-attack when most stuff is dead, or wasting AoE controls like MC and MH for the same reason.
The problems are:
Mind is a setup control set. Early on you sleep this guy, confuse that guy and hold the other guy. Not until you get Terrify and Mass Confuse do you have controls that reallly speed up a battle for you. Before those powers you're much more selective and cautious.
Now mind is a very powerful control set and you can handle 3-4 spawns at a time, but it's not very 'fast'.
Thorns, imo, is the weakest assault set for the simple reason that lethal is the main damage type and probably the most resisted. The toxic bonus is too low and unpredictable to matter much.
Also, impale and thorn burst have to be the two slowest animating attacks ever.
Lastly, thorns range is pretty short and suits melee positioning best, while mind control is more a ranged control. So the two kind of counter each other.
So if you combine a more deliberate and ranged control set with a lower damage, short range assault set, the synergy is lacking. I orginally made him for PvP with Aim and the non-typed control attacks, but we all know where that part of the game went. He was my first lvl 50 dom though, so I have fondness for him, but I'd pretty much choose any of my other doms to run with before him.
Please buff Ice Control.
Aah. Rock, thanks for the great info, DarkCurrent.
I was hoping someone had some experience with the set. I'll likely dip into Mind/Fire, then. It seems to be a pretty solid set for what I'm looking for (Mostly TF spamming, with the possibility of farming once he set up), and the attack animations seem fast enough with a pretty high damage output.
I personally just slapped together a kind of frankenbuild on Mids, but doesn't anyone have a build they wouldn't mind sharing so that I could get an idea of what I'm doing?
I'm finally going to put my mind to leveling a Dominator, after much slacking and putting other builds ahead for some reason.
I'm kind of curious as to how a Mind/Thorns would work out?
I've only ever gotten a dom to about.. 20ish? So I don't know them in and out terribly well, but the power set seems to stick out in my head, in theory, to be pretty good and unique in it's own way.
I'm always open to any suggestions, and looking for any help I could get on decent first time builds.
Thank you ahead of time!