I'm still relatively a new owner of the 500.
Some food for thought....
A big learning curve is needed on organizing the scanner, especially if you like to break things down by geographic area, then whether you want to separate different agencies and then whether its LE, Fire or Ems. I'm not to happy about not being able to toggle at my choice(like the 396) what I'm listening for. Also, disappointed in having to do a lot of editing when importing from RR. Size wise, it's a lot taller and thicker size scanner than the 396.
Sensitivity wise, Its just as good as my 396. It's nice to have NAC decoding(2 LE agencies by my area, though with 1 it doesn't matter since most of the time it's encrypted) I also like the ability to color code a frequency (flashing or solid LED light,wish it was a little bigger). It does have a better speaker than the 396 that I have, though a mute point when I run it through my speakers in the truck.
What it really boils down to is what you're scanning on a regular basis. I think the 500 is a good scanner and well worth the price if you choose to go that route. However, if you're use to the bank\group system, there's a steep learning curve on organizing your frequencies the way you wish. A good way to see what you're getting into is download any of the trial programming software and input your information. If you're content with the organization, then I think you'll be happy with you purchase.
Me, I'm going to fool around some more and see if I can organize it the way I like. I'm not ready to turn around and say I don't like it, Do you want to buy it routine. There's always a learning curve when trying something new.