Re Universal, if you stay on property there are some nice advantages. Most have early park admission, water taxi to Citywalk from some, higher end include express passes (I think), etc. I usually stay at Sapphire Falls, which has the water taxi, but no Express (I already have this so I don't care). Cabana Bay and Aventura are cheaper options. Also, you can use the water taxi from both Cabana Bay and Aventura, they never check where you are staying. Super short walk from Aventura, a little longer from Cabana Bay, especially if you want to safely cross the street to get over to the Sapphire Falls side. Cabana Bay is super convenient to Volcano Bay though.