I had NTB 12-086 installed at Mountain View Nissan in Chattanooga on 12-17-2012, first install of it they had done.
No problems, done in less than two hours, done under warranty at no charge.
After driving the vehicle for five days (~100 miles), my opinion is that the change is modest. A bit smoother brake activation more similar to an ICE with no regenerative braking. Bit less grabby / abrupt.
I have never experienced the other condition that some have reported of a significant excessive braking until the brake pedal is fully released on my fairly early production 2011 LEAF. I think that is a separate issue from what many consider to be "grabby brakes".
Since the software change, I have yet to end up stuck in slow bumper to bumper traffic jam that would probably be the more complete test of the software change.
It is my opinion that a big part of the "grabby brake" issue on the LEAF is due to the excessive "creep" built into the motor control. I have never driven an ICE vehicle with an automatic transmission that moves forward this much when you take your foot off the brake. On level ground most ICE vehicles will hardly even move forward when you take your foot off the brake.
An ICE might gradually move forward at 1 to 2 feet per second. In comparison the LEAF will move forward at more like 5 feet per second. It has way too much creep.
The only ICE vehicle I ever drove that had issues with forward movement when you took your foot off the brake was a 1988 Merkur Scorpio built in Germany. When engine idle was working properly, it would not move forward at all with your foot off the brake. But it had a defective Throttle Position Sensor, and I did experience one dangerous event in which engine speed swung low, and engine control in responding to this had a bad inadequately damped response and raised engine speed to near 1200 rpm, and it abruptly lunged forward at about 10+ feet per second. I'm still of the opinion that most of the Audi unintended acceleration issue was caused by a similar issue. But the few horrific accidents which occurred resulted mostly from the driver hitting the accelerator pedal instead of the brake when this occurred.
The LEAF would be a much better vehicle if Nissan significantly reduced the amount of built in "creep" in the LEAF, or eliminated it entirely.
It would make for much smoother, easier, and safer driving in very low speed / stopped situations such as fast food drive throughs, drive through car washes, or in backed up bumper to bumper traffic jams.
I do not consider NTB 12-086 an adequate complete fix for the "grabby brakes" issue on the LEAF.
Man. Date: 03/10/11, VIN # 2026
Blue Ocean, 2011 SL-eTec