Actually, yes, I think a waiter should be honest about a particular entree. If he/she's tried it, and it wasn't his/her thing, he/she should say so, but at a minimum should explain WHY he/she didn't care for it, i.e., "I found it too spicy/salty/sweet/whatever for my liking. My favorite dish on the menu is X." Or, "this item is one of our top choices".

I'm not suggesting that the waiter disrespect any of the chef's creations, but I think it's perfectly acceptable to make recommendations based on personal likes/dislikes IF ASKED by a patron. I did this just last night when I was out for dinner. The waiter told me that the soup was good, but not his favorite, and he recommended a salad that I might not otherwise have tried. I appreciated his input based on my inquiry.