In my test drive experience--
Mazda 2- better handling, feels faster, looks sportier! But very noisy -little sound insulation, and lots of noise from tyres , so noisy you can't drown it with the radio! Also very few storage spaces , basically weird semi open glovebox, door pockets , and that's about it. On my 2nd test drive the noise killed the deal for me.
Yaris, again looks nice , not as sharp handling as Mazda, but the seats have such a pronounced curve on them I had to return to the dealer after 30 minutes of a day long test as I couldn't continue as they made my back hurt so much. I have got a duff back , so the seats might suit other people, but not for me.
Jazz, first of all comfy seats, especially after the seat mod I found on the Fit forum. Doesn't handle so well if you want to drive like an 18 year old, quieter than the others, seemed well built, lots of storage space, acceptable stereo( not brilliant but OK ). Spare wheels can be purchased on e-bay , I bought a Rover alloy one that fits. Very good fuel economy, I have averaged 51.9 mpg from new, only 4,600 miles though.
My Jazz has 15" wheels, the 16" wheels ones I drove were a bit noisier. I tested The Si , I wanted that, but again the seats are a bit firmer and didn't suit me, but in my opinion a much nicer looking Jazz.
My 1.4 ES suits me , and for me was the best choice.