The gearbox in the Master is 6 speed but is no LFA.
You can be cruising up a hill in 6th gear, decide to go for an overtake and it will take a little bit to change down enough gears. You can preempt this by using paddles to hold lower gears prior to needing the punch which works well. If it's in sport mode it will not shift up unless you tell it to, will bounce off the limiter which for some reason makes me happy.
Drive by wire is a non issue. As touched on by others it's an integral (and heavily, heavily tested) component of any modern car. The likelihood of the cruise control going wrong is extremely low. This is well proven technology by now
Worthy of note is traction control cannot be disabled, this is obviously for good reason because the 2gr will quite break traction in 1st/2nd on event slightly substandard surfaces.
Fuel economy alright, I get 450-480km's per tank (50L to fill from empty). This will increase substantially if you're spending any time cruising at open road speeds, mine is around town/stuck in traffic vast majority of the time. 100km/h is about 1900RPM in sixth gear.
Handling is more than adequate for a road car. Put decent tires on it and you're unlikely to run into its limits at sane speeds. I suspect putting it on the track would make very short work of the front tires however.
These things are very quiet at cruise. They have big thick carpet, sound insulation in the wheel wells and just generally feel good quality and well put together. Compare it to a falcon or commodore and it's laughable how cheap they feel.