I just picked up a Pro-444 on impulse and it indeed does cover up to 470 mhz.
It has FOUR audio jacks, two for each channel (A/B) of a different size. Accomodates headsets with mics so that you have a nice intercom. I don't have a racing headset with a mic, so I can't try that out, but for sure this is pretty cool. The different size jack options means one less adapter to forget when you get to the track. Cell-phone audio is attached to the PC/IF/Phone jack on the right. If you have a racing headset with a microphone, you can talk to the phone.
Antenna is indeed a fixed stubby - no way to change it. Squeezing the antenna feels just like a thick solid rod inside the plastic covering.
Charging can be done in the radio and is set for a 14 hour slow charge. Most of us won't do that internally anyway. Switch inside battery compartment for alkaline / nimh. Takes 3 cells, so if one is going to charge externally, it is best to get a quality charger that can handle odd cells - charging each cell individually. Uniden owners know what I'm talking about.
Programming by hand isn't that hard, but it isn't obvious if you don't have the manual. And once you program in a car/freq, there seems to be no way to delete it later! The only thing you can do is lock it out, or add to it. I'll look into this some more. Without the manual or some practice, I'll bet that many just power-cycle it.
To scan - hold the CAR button for 2 seconds. To stop scanning, hold the CAR button again for two seconds.
SQUELCH: Edit > Setting > SQ
Adjust to taste.
Volume: Tap the FUNC button.
Backing out of menus / edits: Tap the edit button repeatedly to go back. Not intuitive, but it works.
Radio is convex on the bottom! So radio rocks around when set on flat surface. I would have liked a flat surface with rounded edges instead of making the entire bottom convex.