We were there last week. We all went to the e-night on Wednesday (6/30), plus my wife and kids also went on Friday (7/2).
There were 10-15 minute waits at several attractions on Wednesday, but my wife said that everything was pretty much wide-open on Friday (they rode Space Mt three times in a row). If I had to guess, I'd say that a lot of people are winding down their trips by Friday, and are just too tired to stay out that late again.
E-night was awesome. Definitely worth the money, IMO.