Some shooters maintain that leaf springs give slightly crisper trigger pulls, although I doubt you would notice the difference with triggers regulated to Perazzi standards.
The main difference is that if a leaf spring breaks, then the gun will always fail to fire.
This is highly inconvenient unless you have a spare, and the means and knowledge to fit it quickly ? or a spare replaceable trigger assembly such as those fitted to the Perazzi MX8.
The same is not true of coil springs. When a coil spring breaks usually just one coil collapses, so the gun may continue to be usable, albeit with slightly reduced hammer strikes.
I have seen one gun which was still firing with a coil spring broken in two places.
Spare coil springs are also usually much cheaper to buy than leaf springs. So the choice is yours, but go for coil springs for reliability.