want my advice mate? ill giv u it anyway, dont! lol
okay heres mine, DO
mind/sonic will be awesome, the damage will be great from the damage res debuffs, hold +levitate with sonic siphon wil means you'll be a killer. And well with mind, its the best controller out of the lot, SO definately go for it from speculation your mind/sonic will be great. Its just going to be hard finding responses as it is a very very rare set, shame though as its a bloody effective one on paper.
Mind controllers are so good it isn't even true, If you're going to be teaming a lot sonic will be great too, But for a soloer it isn't that good of a set.
My advice as a fellow /Sonic 'troller - don't take the shields, concentrate on the debuffs and control aspects, and Sonic Dispersion - which makes you that much less squishy. As a nod to teaming, I picked up Clarity (which is an awesome buff).
Oh, and slot Sonic Siphon to turn AVs into pussycats. 
@Synaesthetix
"Here, take some more bees with you. You may need them."
Union: FU//LoUD
"that Syn is that that" - Mothers Love
Having got a Mind Controller to 50 I can say that Mind is a fantastic power set. A great combination of holds and attacks (even though us trollers will never do loads of damage, nor should we) and a real joy to play. I solo'd a lot until the mid 20's and found it dead easy - AoE hold, get some damage done, single target holds all round, more damage, AoE hold, more damage, etc, etc. I even solo'd Frostfire using the Mind power set! Get it slotted right with Acc, Recharge and Duration and you're unstoppable.
Don't know sonic (for some reason I went for FF), but it sounds (no pun intended) like a great combo to me.
_________
Gabriel Kane, Lvl 50 Mind/FF Controller
Lucius Kane, Nec/Dark Mastermind
This does sound like a good combo on paper. I have a mind dominator at lvl 38 and can confirm that mind/rocks in the control department and does respectable damage (mostly psi, which is nice). S
Sonics is also a very nice looking set....in terms of powers, unfortunately the sound effects and animations have put me off too much to lvl one up. I had a bubbler though and this looks like the set bubbles wants to be at the moment (come on devs, give some love to bubbles!)
And i would skip the shields too...but then i'm selfish 
and i've also spent too much time as a buff-bot. Never again i say! Never!
I miss him in the weeping of the rain;
I want him at the shrinking of the tide;
The old snows melt from every mountain-side,
And last year's leaves are smoke in every lane;
But last year's bitter loving must remain
~Edna St. Vincent Millay
Hey folks, happy new year
Thought I would make a Mind Sonic controller because i havent seen any around before, can anyone give me any advice or feedback on my decision?
Thanks