Wow... bumping a year old thread to say it's "reported"? Nice necro.
But since this thread is now active again, I'll add my 2 cents on topic.
I've only played 2 milsim events and about 5 skirmishes to date. From that, I can say that I tend to like milsim more. However, there's has to be a balance. I like the realism, tactics and scenario of milsim better than skirmishing. To me, it's just more of a rush, and it's a cerebral, as well as physical experience, whereas you get into the combat mindset more. Even though you know that you're getting shot with BBs, you still have a bit of that survival / self-preservation instinct giving you an adrenaline rush.
However, I tend to dislike the uber-hardcore milsim mindset where you have to have 100% accurate gear and tactics, where "improperly" geared up noobs are frowned upon, etc. Airsoft is a game that should be enjoyed by all participants, even though they can't afford an accurate full loadout or high end gun. As long as someone is there willing to play the game within its rules, then it's all good. Luckily, the 2 milsim events I attended (Op Drug Bust and Border Wars 2) were sort of "relaxed milsim", so it kept the fun factor pretty high.
However, I do enjoy skirmishing too. Playing a fun game with no rules and just mindlessly shooting each other can be a whole lot of fun too.