Native Pittsburgher here! Kennywood is packed with rides. We've been to other parks and they had very few big rides in the park . I guess the Phantom is the new best thing at Kennywood but the Thunderbolt and Jackrabbit are storied legends of the park. If you have not been at parks where the rides are wooden roller coasters then this will be a real treat fir you.
Remember this is not Disney so don't expect a Disney experienced is a Pittsburgh experience. If you are around in the summertime you can try out Sandcastle also.