I have bought all of the Diner Dash games up to this point. Playfirst (the game maker) and Big Fish Games merged, and now Big Fish has all of their games.
I played the trial period of this new game, and it has some interesting new twists in it that aren't just delaying tactics to make the game more difficult. I appreciated the new things they added (such as rain). However, the music isn't the same and the sounds when you click on various items sound different to me. I don't hate them, but they don't sound exactly like I prefer DD games to sound. I guess you get used to certain music (like the Intro to the Nancy Drew games) and you expect to hear that music when you turn on a new game.
I've decided to wait on the regular edition to come out in 2 or 3 weeks at Big Fish before I buy the game, but it does seem as though they've added a lot of new stuff, so I look forward to playing all of it.