We live in Langhorne, PA. Home of Sesame Place.
My kids and DH get season passes (he's home all summer). I can honestly say it's great...during the week in June...and not great on weekends or Fridays or in late July and August.
So if you go on a weekday, in June, it's lovely- clean, not crowded, and fun for kids. The staff is a lot of high school and college kids, they perform best without the pressure of large crowds.
After about mid-July, lots of busses of people are there every day. The "maximum capacity" is when the parking lot is full...and when the park gets crowded, it gets really bad in there.
I don't bother with a season pass for myself, I'll pay admission for a day or two to go with them in June on a weekday.
But you'll never catch me there in July or August.
There are a few nice hotels very close to the park. And a Mall, Target, shopping centers, etc.