I also had the opportunity to have Byte Knight do an upgrade to my Flashback and I wanted to post my impressions of the unit.
The setup document was easy to follow and I soon had an Intellivision controller in my hand playing Deadly Discs for the first time in decades.
As the other posters have said, the colors, sounds and feel of the games being played in the jzIntv emulator are spot on. The original Flashback's primitive menus and sometime spotty emulation are laughingly comparable to the experience of playing the Ultimate Flashback.
Yes, the upgrade could be considered expensive, but I found it completely worth the money. I would be shocked if a Gen2 Intellivision Flashback even comes close to this unit.
I really, really can't help myself with the comparison.. But, the Ultimate Flashback is the closest thing to the real thing.
Now, if I could just get my damn overlays to show up..