Followup: I did road test it, and I've already switched back to the LCD
The display was very responsive and probably would be less prone to extreme low temps BUT
1. It drew a LOT of current. I couldn't keep my finger on the regulator, even on lowest brightness setting. It eventually went into thermal shutdown. The input diode wasn't real happy either.
2. If it gets into direct sunlight, it becomes completely unreadable even at highest setting. I tried to bounce it off the windshield, but couldn't see anything.
3. it is like 3.5 times the cost of an LCD.
So I cannot recommend the VFD approach at this time, ah well. Will update wiki.