We visited in June whilst on a tour of west coast USA, and planned to be at universal on a weekday as we thought it would be quieter. It's hard to say whether this was true or not, as it was still busy. On average we queued for 40-60 minutes per ride/ attraction.
Tried to get some kind of discount on tickets online beforehand (both from uk and whilst in LA) but there didn't seem to be any (unlike Uk theme parks that always have an offer on somewhere). But it is definitely the best theme park I have been to- it walks all over all the Uk ones in terms of layout, themes and quality of rides and shows. Very enjoyable for 2 film loving, fun loving adults. Arrived around 10am in the morning and had a full experience by around 4/5pm. Expensive, but definitely worth it. Transformers ride was the best ride I have ever been on!
The parking is 15-20 dollars depending on which car park you use, but the 'value' ones are close enough not to warrant paying the extra. And you walk through a shopping/ entertainment centre to get to the theme park itself which is nice to experience. All fake looking, but good fun. Choice in places to eat and better value than inside the park (we took packed lunch with us, but bought pizza outside for dinner afterwards which was very reasonable.) You also got a rebate on parking if you went to the cinema so we watched a film as well to finish the day off.
Not sure whether I 'need' to go again, unless they change the rides significantly. Might be different if you have kids as I believe you can get an annual pass for little more than a day ticket. But would certainly recommend going if you find yourself in LA and would go to the restaurant /cinema complex again.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.