We've eaten at both. If you're not in it for the characters much at all, I wouldn't bother paying the extra money they charge for it being a character experience, but that's just me. Also, if I'm not in it for the characters, I'm not into having to get up and go through a buffet, I like to relax and have someone else do the work for me.
As far as food goes, if you're particular about food quality, I guess CP is a little better in that regard, and it might have a little more variety to choose from. However, I never have any issues with Tony's food. It tastes just fine, though it's pretty much strictly italian.
I try to make Tony's a tradition on my trip, as I love the atmosphere. It's right at the front of MK, and the theme of the restaurant pretty much matches all of the Main Street USA. Lady & the Tramp is one of my all time favorite Disney movies, so its nice to be in a place themed as such. And our service has always been EXCELLENT. We've been at busy and not so busy times and either way the servers were very attentive, always generous with drink refills and went out of their way to talk to us and make us feel welcome. They treated me like a princess on my birthday too.
The atmosphere in CP is not bad either, though. But I attribute that partially to the characters...but it's also very lovely with all the natural lighting and I think the decor is very pretty.
Have fun doing whatever you decide!