Awhile back, I was debating whether or not the 10db of increased Ka-band sensitivity was enough to justify the increased cost of replacing my Pro-73 with a 78. Now that I have the 78, I can say it absolutely IS.
And I haven't even TESTED the Ka-Band sensitivity yet.
Here's my reasoning:
1. The Filter settings to block out Cobras are amazing. I don't alert on leaky POS RDs any more, and that eliminates a HUGE chunk of the falses my Pro-73 was giving me. I didn't realize how much the thing falsed on RDs until I got this one. This feature alone is worth it.
2. The 1-2db increase in K-band sensitivity has provided some very nice ramp-up warnings on both Po-pos and Your Speed signs. Since they use K-band a LOT here, that's a huge thing for me.
3. The improved features are great. I love the auto-dim feature, and the fact that it's louder makes it much easier to hear over my stereo. I like the ability to turn off bands individually, and the buttonology is far simpler.
Those three things alone--and especially that first one--make it worth it. So I'm answering my own question: yes. It's worth the upgrade.