The camera is the most notable difference. In addition, the P3P comes with a faster battery charger (cuts down the charging time by 30 minutes) and has a max bit rate of 60 Mbps (instead of 40 Mbps) which is a must-have if you plan to fly with FPV goggles.
Ok so the charging and goggles wouldn't be an issue, and 2.7k instead of 4K doesn't really bother me, so an advanced would probably be good enough for me
Just don't want to be missing out on anything special
There is more difference than you will see on DJI web site. The downlink speed on the P3A is limited to 2 Mbps while the P3P can go as high as 10 Mpbs. Both display 720P at 30fps but the P3A display has artifacts and pixilation. Wheras the P3P display is crystal clear. I fly a P3A and don't find the artifacts to be a major problem on my 7" tablet display. But the first time I displayed live video on a TV I was shocked. The video recorded on the bird's SD card is sharp and clear and more than adequate for me.
However I have been thinking about flying FPV with HD goggles and several forum threads say you need the clear display of a P3P for that to be worth while. I may try upgrading to a Pro camera as described here: Upgraded my Advanced gimbal/cam to Pro...WOW!!!. There are several threads on forums around the internet discussing this difference.
From all reports I have seen, the range is the same.