15X & 780...can't tell any noticeable difference here.
As I stated I have both the 780 and the 15X. And quite honestly they compare as far as performance goes the same. Both hear weak comms the same. No overloading. No intermod. No desense from being so close to DMAFB. The 15Xs are just over year old purchases, new.
Using Motorola Syntor speakers on both
So it's whatever you decide either would be a great choice.
Everybody is going to have there reasons for specific versions.
The 780 is been out of production for quite a while now. I have heard issues with the LCD panel acting up for some people. Fading and such. Getting repairs and parts my be an issue for some.
I cut my discones to shorten them using an antenna analyzer since I only monitor milair V/UHF freqs. I did what was best for my monitoring. And it works just fine.
Don't much care to listen to police calls anymore.
Listening to the Davis Monthan AFB P25 system is boring as the security forces more often than not are encrypted. Flightline activity ho hum.
So far I can hear on my combo setup are a/c up by Phoenix and Utah , various ranges, refuel track comms and some test a/c ops. My 15X is usually on the most.
My antennas are mounted one a 1 story house and not even above the roof peak.
Again, its whatever floats your boat.
Have fun, listen.......