Sod it, I put spaces between the comparative specs, but they vanished. Just imagine them there ,and it`ll get clearer. ISAF rating for Mozzie is 1.14 as opposed to Sirena at 1.15/1.18, so the Mozzie is faster .
If I were a junior sailor I know which boat I`d prefer to pull up the beach at the end of a hard day`s racing (Hmm, the one which weighs the least ?)