I got my PMA-450 back in late 2014 or early 2015 - I think when it first came out. A year or so later, they came out with a revised version (PM-450A) with a brighter display and some enhancements (I don't know what). So, right out of the gate, my "brand new" audio panel was outdated. Now, they have come out with the PMA-450B, which has multiple Bluetooth connections, so mine is a real dinosaur.
I like the Intelliaudio, and I like the built-in Bluetooth and intercom. But, I went from a KMA-20 with toggle switches to the PMA-450, and I don't really like the menus.
What I like:
1. Intelliaudio - kind of a gimmick, but I do like it.
2. Bluetooth just works. I can call for a clearance, or whatever and it works great.
3. Basic operation is via pushbuttons, so most things (switching to COM 2, etc. ) are easy.
What I don't like:
1. Going to the menu for anything. I just don't like futzing with the menus. What a pain! I'd rather have buttons. I was
2. Lack of separate volume control for co-pilot. The other PSEngineering audio panels have this, but not the PMA-450. I guess it doesn't affect me much, but when I'm riding in someone's plane that has that feature, I like it.