@andre:
Big Mom Pirates>Beast Pirates>Whitebeard Pirates for me. Whitebeard's group have cool abilities, but none of them are super interesting even after being focuses in Marineford and Oden's background. That is unless we count Oden and Whitebeard themselves. The Beast pirates are pretty interesting and that's without being fully fleshed out yet. All of the Tobiroppo are cool besides Sasaki (for now) with Ulti, Black Maria, and Whos Who being the highlights. King is kind of a non-entity at this point, but I'm expecting that he'll be pretty interesting given how much is still left to mystery. Queen is a force of nature and has been wildly entertaining since his role in Udon. Jack may have been beaten by Neko and Inu, but he's been much more interesting than Smoothie, Pica, or Vista/Jouzu.
Big Mom pirates are still GOAT, but that's mostly because of the extras and how great Katakuri is. I actually enjoy the gifters, but they aren't as great as Big Mom's giant family and the variety of Devil Fruits and fighting styles they have. I'd easily take them over Whitebeards extras (guys with swords and guns) and even his allied pirates who were also mostly guys and girls with swords and guns. If the potential of King, the Numbers, and Sasaki is met then they'll end up being really awesome. I can see why anyone would put Baroque's Work above them, but I don't see the argument for Doflamingo's pirate crew. Senor Pink is the only real standout among them.
I admit i would probably rate the Beast Pirates higher if their powers and fighting styles were more varied. Queens cyborg-Zoan is pretty interesting, but a whole crew full of Zoans with most of them being dinosaurs? Bland.
As for WB pirates I think one would have to have a really low opinion of Ace to rate them below Beast Pirates