The Alfa has this and I disable it 99% I'm in the car. Not because I don't like start-stop tech, but because on this particular vehicle, it takes too long to engage when I release my foot from the brake. I drove one other vehicle with this a loooooong time ago, a Saturn Vue. On that vehicle, the re-ignition was seamless. From what I remember, my foot wouldn't completely leave the brake pedal and it had fully restarted. On the Alfa, there's a hesitation of sorts, almost like the car is trying to figure out if I'm actually going to hit the gas. If it weren't for this, I'd keep the system engaged (once the engine is fully warm). Where it really comes in handy for me is that if I'm driving with it disabled and I'm at a train crossing or a known long red light, I can hit the deactivate button (to activate) and it will kill power to the engine but not the other features; radio, heat, a/c, etc. and when I'm ready to roll again I simply deactivate again and it kicks power on without going through an entire starting cycle which would temporary kill those features.
For those stating that these systems cause increased starter wear. That's simply not the case. The starters in these vehicles are not like an ordinary starter, they're specifically built for this kind of usage.