I never experienced an EF mass, since the city I lived in at the time didn't offer the EF (and then only once a month) until about a month before I moved away. From what I have heard from people who prefer the OF is that the EF is somewhat cold and/or stuffy. Again, I have no opinion, as I never experienced one. I experienced a few less-than-by-the-book OFs, though (jazz bands doing patriotic songs during the Mass because it's 4th of July? Check!). I don't mean to put words in any RCs mouths, but I'd guess that this is often one of those "general atmosphere" things, with the idea that the OF as often celebrated is either too irreverent, or (according to some of the more extreme anti-OF crowd) actually generates/encourages such irreverence by its form.