This was my 9th Otakon this year and I've only had one major issue with Security. It was when I bought my complete resin blue gun (Non-firing, non operational, and a lovely light blue) and I was kicked from the convention because it didn't have an orange tip (thankfully I was let back in after I got one painted on); but my issue there was my friend had a green light gun that didn't have an orange tip and he was fine.
I've never had an issue with waiting on the lines, it took me literally 10 minutes to get on line, walk in, and get my badge on Thursday. My first Otakon it took two hours.
I also spend a lot of time in the Artist Alley and heard a few complaints, but never anything so much so that it made people have a miserable time.
I attend Otakon to go with my friends and to have fun, and for 9 years I've done just that. I've had fun and a lot of good memories to keep going with. 2013 will be year 10 for me; definitely gonna make it rock! :>