For clarification, the characters are only at breakfast - not dinner (in case someone reading the thread didn't know).
I would rate Storytellers even more low key and laid back than PF at WDW. When we were there it seemed like mostly adults and just a few families (May 2004). So it wasn't near as hectic as PF where most people are there for the characters first and food second. Maybe because you can order from a full breakfast menu? You also won't have the organ playing in the low ceiling of PF. The noise surroundings alone makes Storytellers one of the calmest and most relaxing character meals we've done (and we've about done them all - WDW and DL).
It seems like if people aren't in the parks and are doing a character meal they are at Goofy's first, and PP second. I think a lot of that has to do with the characters. Goofy's has a lot and a good variety (we've seen up to about 10 different characters there for brunch). PP has Stitch, which is one of the more current characters that kids are in to. Storytellers just doesn't get a lot of publicity.
I think when we ate there a couple of years ago they only had 3 characters - Chip, Dale, and Pluto. We're heading back in 3 weeks, and we're having breakfast (and maybe dinner) at Storytellers again.