Hi Jildy
Myself and Mrs fm stayed in the Parco Dei Principi a couple of years ago - even though it is rated 5 stars we would not really recommend it.
Apparently it is famous for its authentic '60's art deco design - it is completely '60's art deco - everything from the tiles on the walls, to the ashtrays, to the phones and TV's in the rooms etc all 1960's - unfortunately neither myself nor the Mrs are great fans of Art Deco so we just thought the whole thing looked dated ! That said the view was unbeatable and the 300 meter ride down to the beach in a lift was kinda cool. Also food wasn't great and the pool could have done with a clean.
We did walk through the Bellvue Serene (I think) and thought it looked fabulous - quite a heavy Baroque feel to the place but looked salubrious.
Try and get one of the hotels within easy walking distance of the Piazza and the harbour because that's where everything happens.
Anyway, despite our problems with the hotel we loved Sorrento and would love to go back some day
efm