I've had the Pro Flo2 on my build since day one and that version is ~20 years old at this point. I will say I love it- or actually, loved it. It was great until something happened which I haven't been able to troubleshoot.
Due to the issue, I may not be the greatest reference point, but the car ran great (FMS 302 longblock w/350h/350tq) and was extremely streetable. Cold start is fantastic, idles great, runs out to whatever redline your hardware will tolerate... I even got ~21 MPG on a 4 day, 1000 mile trip through Oregon and California.
The other interesting thing is they use a number of OE parts. I replaced a voltage amplifier- it was a late 90's Vortec SBC unit, not a specialty piece from Edelbrock. I believe this is the same for their injectors, MAP and other sensors, etc.... There are a couple proprietary ones still though.
I have tried to fix mine a handful of times, with a casual amount of effort but without success. Edelbrock's tech support's recommendation was to upgrade to the new system. I didn't want to jump off that $2k bridge without investigating first, but I have had other irons in the fire, and it does run so I've used it sparingly. The issue is that once the engine bay heat soaks, there is something with the ignition which causes it to stutter and stress the alternator. I have a feeling it is something simple because it runs like a champ right up to that point, and it doesn't always do it. I also don't want to spend $2k and have it not actually be an EFI system issue.
With all that said, I really do like it and would do it again. I am a fan of this EFI. I hope that helps.