That's like a "who's your favourite kid" question!!
They are all awesome in their own right - just depends on what YOU want.
Cabana Bay -- Awesome vibe - it's like Frankie and Annette's Beach Party. The pools are amazing - lazy river? Yes! Waterslide? Yup! There is a bowling alley upstairs, the Bayliner Diner is like Landscape of Flavors (and the food is actually really good), you can walk over to Volcano Bay. The rooms are awesome 50's vibe, but still comfortable. All of the rooms have a fridge, but the family suites have a kitchenette-ish area (fridge, micro, sink, cupboards) and a living room with sofabed in addition to the 2 queens. No express, so we only do CBBR with a split-stay, or when it's just a couple of us, and we don't mind using the single rider line when it's busy.
Sapphire Falls -- Gorgeous. It is Caribbean cool. Still fairly new and pretty; the rooms are laid out well, but small. The water taxi is a wicked perk - you don't have to go through the main security hub EVER! You have your own little security crew at the dock before you even get in the boat. Awesome time saver in the mornings! Not much food that my picky kids would eat there though - they still really like the food court at CBBR, since everyone can just go get there own and meet up so mom can pay! lol No express either, so when it's busy, we gravitate more to RPR.
RPR -- still my favourite. I love the tropical feel, especially after the refurb/renos. Love the lobby, and crossing the bridge as you enter. It just transports you, you know? I love grabbing a coffee in the morning and sitting in the centre area and just listening to the water. The pool is nice (the food and drinks at the Bula Bar are awesome), but geared for little ones with the splash park area. There's a great little beach if you actually wanted the "vibe" of sitting in a beach chair by the water with a drink.
Downfall - no starbucks???
Portofino Bay -- SOOO authentic! It's crazy. Last year was the first time I worked up the nerve to take my heathens to LPB (Clampetts go to Maui, anyone?? lol). It's stunning. Like jaw-drop, wow stunning. The rooms themselves are just fine. You can tell it's the oldest resort, but the bathrooms have been redone, and they are super nice - like the size of my bedroom at home?. We didn't make it to the pool (only one night there and it POURED), but I am looking forward to it this trip. The entire resort, from the water taxi dock, to the giant marble fountain out front - just oozes old world charm.
Hard Rock is one we've never stayed at. I just don't "feel" it. I love that it's really close, but it's always a price thing for me there. If I could get it cheaper than RPR or Portofino Bay, maybe... but the feel is more of a party, upbeat, funky resort. I really like the relaxed, beautiful "vacation-y" vibe from the rest.
Sorry for the book - I'm kind of an addict!