Jen D.
Yelp
Every time I take my kid to Great America we have an excellent time. It's not that the people complaining are wrong exactly, it's that you have to flex to how the park works to maximize your fun.
First, this is not Disneyland. Operations are inefficient when it comes to filling up the rides, so lines quickly grow...possibly on purpose to encourage more purchases of their fast pass line hoppers.
Second, know who rides which rides. Parents with little kids show up in the morning, teenagers in the afternoon. That means an hour or two of minimal lines for thrill rides if you show up when the park opens at 10.
Once the teenagers arrive how long you have to wait is mostly determined by how many people can fit on the ride per run. Want to ride the Psycho Mouse that only takes four (and is "kid friendly" so littler kids are in line too)? By mid day you could wait 2-3 hours. On the other end, the flight deck seats something like 32 so even a decently long line might take only 20 or 30 minutes to get through.
In our opinion the best rides in the park are, in order, the railblazer (seats 8, so long lines in the afternoon), tower drop (16, but also people are freaked out by it so lines are manageable all day), flight deck, mass effect 3D experience (seats lots but also is looooong, only go early), delerium (seats a bunch but also a longer rider so can develop a line), the orbit (no one seems to know about it and it seats 16. Have rarely waited more than one cycle even mid-afternoon), psycho mouse, and the tiki twirl (seats...many, but a longer ride so can develop a line. Also the seating is super uncomfortable).
Also go on the weekend. Even though it's busier they sometimes don't run all the rides mid-week to save on staff.
On to the food...which is very expensive and not very good. Probably the best is the chicken tenders from The Market (the place with a whole bunch of different little stations), and probably the worst is the burgers from the same area, which appear to have been pre cooked hours before and are rock hard.
But even tho they say no outside food I've never had my bag checked for that so I'd just bring my lunch if I were you. Or, if you can be patient and are going to be there all day, get one all day meal plan to split for each two people. Lets you get a meal every 90 minutes, so if you split them you just end up eating 4 or 5 smaller meals instead of 2 regular sized ones and pricewise it works out to ~$18 per person for lunch and dinner combined.
Also, hot tip: check to see if the date you are going to go allows add on tickets for season pass holders. If it does, the cheapest approach is buy one gold season pass (which includes free parking, otherwise that would be $35) and then buy add on tickets for everyone else. Even with just two people that will be cheaper than buying two single day passes and parking.