For me, it is really pretty simple. Despite the myriad long-winded defenses of skill challenges that I am sure you have read, and regardless of all the usual tidbits of advice that have been floating around since their inception, it is my opinion that Skill Challenges do irreparable harm to roleplaying. I like roleplaying to be free-form. I hate adding structure to it. I much prefer calling for checks on the fly, letting the PCs actions flow naturally, and having the possible repercussions of their failure come to me organically, rather than devising some pre-plotted outcome based on how many dice rolls a party fails. It was just a bad idea. I can respect that they were trying to add another mechanism to gain experience points outside of combat, but the whole "Three strikes, you're out", "Let's make some lists that extrapolate hypothetical skill checks, then force a few into every adventure", etc, was just a bad idea.
I realize that products like the DMG 2 and the Rules Compendium try to massage this a bit and offer alternatives, but to me that is just back-tracking on a crappy idea; polishing a turd if you will. It is too much, too late. It is kind of like when someone says, as if it is the secret of the universe, "Don't tell them they are in a Skill Challenge." I get two things from that statement. One: Skill Challenges are such a downer that alluding to the fact you are running one hurts your game. Two: you must not have a very high opinion of your players' intelligence, because any fool can tell when you are running one, whether you say so or not. "But it's different at my table." Perhaps it is, and I am happy for you if you like them. Seriously, I am. I just do not use them, and you won't see them in the magazine's adventures.
Now am I saying that PCs having to use some skills during a combat is a bad thing? Of course not. Am I saying that there shouldn't be consequences for failure? Of course not. All I am saying is that in my experience, roleplay works best when it is loose and natural, and there is no solution to Skill Challenges that I have ever read (and I have read hundreds) that works as well as simply not using them.
I hope nobody took offense! As always, I am interested in your thoughts, so leave a post!