We have done both in the past year. If characters are not an issue for you, then Id stick with Cape May. We thought the food and service was great. We were seated within minutes of checking in to our reservation, and we loved exploring the Yacht Club/Beach Club after dinner.
The characters at 1900 are a riot! We enjoyed our meal, but mostly because of the characters. Service was slow, and food was good but not great. The buffet lines were very crowded, compared to only a few people at a time at Cape May.
Also, we had to wait 40 minutes to be sat at 1900 -- which caused us to miss Spectro that night!
If characters are not important to you -- Id go with Cape May. The only thing that makes me lean towards 1900 is the chance to meet Cindy and the gang!