I was just there Saturday
The Studios were DEAD Saturday morning - IOA seemed busier, but by the time we got over there (and finished eating at Mythos - yummmmmmmmmmm) it started to rain.
We visited Universal on Wed. 8/29. It was not crowded at all.
Our shuttle was at least an hour late picking us up (wee bit confusion on the pick up location at our resort) so we didn't arrive at the park until almost 10am. We immediately went to see Shrek, then Twister and rode Mummy before 11:30. We went on Earthquake, Jaws, Men In Black and saw Terminator before 2pm.
So, fortunately, even with the late start, we still got to see and ride everything we wanted (except maybe ET and perhaps Beetlejuice)
We were at IOA Sat. 9/1. It wasn't crowded. DH asked someone in Jurassic Park about the crowds and she expected it to be busier in the afternoon-it being a holiday weekend, a Saturday and folks expecting later hours when they were in fact only open until 8pm.
We arrived at the turnstiles about 15 minutes before 9, just before they opened the gates (which they did at 8:45).
We turned left and went straight to Hulk. The wait was about 10 minutes, as was the case for most attractions throughout the day. The tip board we passed in Suess Landing in the afternoon listed most attractions in the 5-10 minute wait range, with the exception of Spidey at 30 min. (glad we got to that one early)
We hit many of the major attractions - Spidey, (skipped Storm Force and Dr. Doom), Ripsaw Falls, Jurassic Park River Adventure and Dueling Dragons before noon.
We continued our counter-clockwise adventure through Lost Continent, going to Poseidon's Fury (rain started while we were inside, so we just missed you Ileana) for the 12:30 show. We skipped the 8th Voyage of Sinbad.
In Suess Landing we rode Cat in the Hat and had lunch at Circus McGurkus, which pretty much ended our day around 2pm.
We needed to catch our shuttle back to WDW at 3:15, doing a little shopping at The IOA Trading Company and Margaritaville on the way to the parking lot.