There's a family story that sheds light on how good "biggest" can be. My mom, brother and I were making chocolate chip cookies about 20 years ago. When they cooled off enough, Mom said we could have one. My brother looked over all the cookies and picked the biggest one. He looked at the top. No chocolate chips. He turned it over to look at it. No chocolate chips. He ate it. No chocolate chips. My smaller cookie had plenty of chocolate and I was more satisfied with it than he was with his big cookie. See if you can ask anyone before going to a big cookie conference because it might not have any chocolate.
Also check out who is presenting there and if your genre is covered or specialized there. Look in the magazine because they always have conference listings or the website might have listings. Think about what the conference will offer you and how it will help you be a better writer.