Either will get a knife as sharp as it can be, if done correctly.
The main differences are speed and price, in my opinion. You have to keep in mind that the Tormek SG-250 wheel, which comes with the basic kits, uses aluminum oxide abrasive, so it's not ideal for sharpening steels with significant vanadium carbide concentration. If you plan on sharpening a lot of wear-resistant steels, you'll want to invest in diamond or CBN wheels in at least two, and preferably three, grits. That's another $600+ on top of the price of the bare machine.
As for speed, I have CBN wheels in 160, 400, and 1000 grits. I can reprofile a wear-resistant blade in Maxamet from 20° to 15° in 10-15 minutes. That would take an hour or two with a fixed-angle system like the Wicked Edge. On the other hand, if you resharpen at the existing edge angle, both systems will be relatively quick.
So, I would say it comes down to your use. If you only sharpen occasionally, I'd go with the WE or another fixed angle system. If you sharpen a lot, the Tormek will save you a lot of time. It's also worth mentioning that the Tormek can sharpen damned-near anything with the right jig (but the jigs are also not cheap!).