The talk isn't about the lever itself. It's the master cylinder. There's good reason for it in my opinion. There's a noticeable improvement over stock for most bikes, especially if you do track days or race. Most race organizations have banned them for supersport competition (bikes are regulated closer to stock in these classes). They don't seem to ever fade, even when the brake fluid should be toast.
I like the different bend on the Pazzo levers. They also look nicer and crash better. Between the regular and shorty levers I like the shorty but that's just a preference. My brakes seemed to feel better with the lever on there over stock and didn't seem to bottom out on the bar as easily.