We like both. But Liberty Tree is a sentimental favorite and we try to eat there each time we visit. We were just there earlier this month and lunch was excellent - try the Colony Salad! It is a cute restaurant and we have always found the service to be terrific. The foyer was jammed with folks in early May and the wait was over an hour; luckily, we had ADRs and were taken on time.
The CP is a lot of fun if you enjoy the characters. We have only tried lunch there - on several occasions - and sometimes it is better than others with regard to variety and service.