The long standing attitude towards named units (i.e. special characters) has been that they should not be allowed in any kind of competitive event. While some events have eased up on this restriction since 8th edition arrived, most large scale events have continued this outdated practice of not allowing them. That changed this year when the Midwest Rampage decided to open the field to them.
Looking at the various threads and blogs from folks that attended this year's Midwest Rampage, the general opinion seems to be that special characters did not impact the tournament in any significant fashion. To quote some of the folks that attended this year:
I ran into Archaon and Mazamundi. I broke Archaon's unit through hex and augment spells and ran him down. I killed Mazamundi with an augument spell (mindrazor). They were enough of a threat that I had to deal with them. I didn't think their special rules and items were worth the points because they were fixed (you can't customize them). Necarch from IWFB.org
no, actually I think when they got hit with dwellers sometimes people cringed. I don't think anyone with special characters got any top places, and I didn't hear of any complaints. Brawndo from The Waaagh Cast! Forums
I saw Shadowblade & Chakax. Shadowblade got peppered by chameleons. The only influence chakax had was convincing me to tie up the TG unit with throw-away. Domus from IWFB.org
One of the things that I have not seen is whether or not anyone used Teclis or Kairos, as these two models are the ones most often cited as a reason why special characters need to be banned from play. While the results of any single tournament should not be taken as conclusive evidence for either side of the argument, I do find it interesting that when given the option, people elected to use what they want and yet still maintain a great atmosphere. Good Job Midwest Rampage!