Based only on what I've read both should perform well but I don't have any first or even 2nd hand experiance with either.

I like the idea of a 338 Fed, which is really just a 338-308 wildcat that now has a home. I love my 338-06 so I would think a 338 Fed would do basically the same thing except with a shorter PBR. Should be very easy to reload if you can't find a factory load that you like. You only need 308 brass and 338 bullets.

The 30 TC is just a 308 clone from what I have read. Since it was released I have seen and heard very little on it. I would avoid it, I would think its DOA.