Congrats on the i20! It is one hell of a car :)
Last week I took a long long test drive of the Amaze, needless to say the sales guy wasn't too happy.
As far as visibility is concerned, I think the Amaze is much better than the Dzire. The Maruti's traditionally are not too good in this department, be it the Swift, Dzire or the latest Ertiga. The Amaze does have blind spots when reversing, but I guess that is true for any big car.
The brakes on the Amaze are a revelation! They aren't spongy but not too tight either. I felt really in control. I am against those extremely hard disc braking systems, as they can be very dangerous in sudden braking circumstances. The ABS
added to the confidence immensely.
I couldn't find much body roll in Amaze either. And of course, the space! The boot is immense in front of the Dzire, so is the rear leg space. Yes the engine definitely makes its presence felt inside the cockpit, but I found that useful for driver feedback in heavy traffic with windows up and music on the system.
All in all, I will give the thumbs up to the Amaze!