I agree with this. We have been to Disney numerous times and eaten at nearly every sit down restaurant in WDW. We are pretty easy to please. Hollywood and Vine is one of the only WDW restaurants that I did not enjoy and felt was a ripoff. The only reason we went is because of our 3 year old who loves the Little Einsteins/Playhouse Disney.
The lunch buffet is expensive enough, and we also had to pay the in-season surcharge of $4 per person or something. I think my son's lunch buffet was like $16. Completely ridiculous. But if the food was excellent I would be happy to pay it. The food selections were very poor/boring, nothing looked particularly appetizing and it tasted marginal at best. Nothing was truly disgusting, but it wasn't good either. The desert selection was awful and the ice cream machine kept breaking down.
The character interaction also wasn't great. We waited forever for my son's favorite, June, to come by. She never did and we had to ask a server to have her come over to our side (several others were waiting for her too).
All in all, not an experience I would ever choose to repeat. If your kids have to see Playhouse Disney characters, I would suggest the live experience on stage at the Studios. I would not say avoid this place at all costs if the characters are a must, but just know you will be getting marginal to low quality food at very high prices.