I listen to the North Carolina VIPER 800mhz system here in Raleigh every day. I just finished updating my 396T.
There were no P25 issues prior to the firmware update, so I don't expect any before/after changes. What I hope to see with this update is EDACS beeps while monitoring the Montgomery Co. Texas system.
http://www.radioreference.com/apps/db/?sid=58
I should be back in Texas next week to try it out. For the sake if comparison, I used to
monitor that EDACS system daily with a 246T and the beeps were so bad I just used my PRO96. The last few times I was there with my 396T, it had the same issue with beeps (just a week or so ago).
There is a large EDACS system south of me that I can try out while mobile, but I don't listen to it from home since it's too far away to get good enough reception to scan.
So far, after 20 minutes of monitoring the VIPER system, I've heard ONE short 'motorboat' burst but I wasn't looking at the display to see what TG or frequency it was on at the time.
As for the AGC performance I have not noticed any real change. After I listen for a few days and do some side by side comparisons with my PRO96 I'll know more.
I was hoping there would be a suprise NAC decoder added into this firmare update though.