Like Dave Salls, I took the plunge and converted from a Qjet carb to a Holley Super Sniper 650 TBI system plus the Hyperspark distributor for custom timing curves. It was dead easy to get the engine running with this system but dialing it in is an ongoing process. I had an Idle Air Control (IAC) valve go bad in the first weeks, Holley Tech Support was quick to provide a replacement. Then a few months later the car just died after a cruise to the neighboring town for lunch. Luckily, I coasted into a gas station and quickly diagnosed the issue as no spark coming out of the ECU. Got a couple friends to help me get the car onto my trailer and get it home. Again, Holley Tech Support was quick to respond. I sent the unit back to them and they sent me a brand new one as soon as they verified mine was indeed defective.
The biggest issue with the conversion to Holley was RFI. I had to reroute wiring to separate power and signal wires, move the Safeguard box to the driver footwell to shorten the wires and shield the coil wire as it passes too close to the Sniper harness as shown in the pic below.
A couple months ago my Learn Table told me I wasn't getting enough fuel under boost. I found my fuel pressure regulator that I'd used with the old EFI system had gone bad. It took a while to figure that out since I had no way to monitor pressure from inside the car. So I fabbed a temporary mount for a gauge where the left hood access panel mounts so I could see the gauge from the driver seat (see pic below). After that I started researching if there was a way to get fuel pressure to display on the handheld screen. Lo and behold, if you add a pressure transducer in the fuel line and wire it into one of the unused ECU input ports you can program fuel pressure to appear in a custom dash display! Learn something new every day.
I've taken an on-line course to see what else I can let the ECU take over. My 2 speed fan is controlled by the ECU which lets me vary the turn-on, turn-off settings on the fly. I'm looking at wiring the AC the same way and eventually I'll control boost via two solenoids.
Anyway, it's been a learning experience that I think has been worthwhile, can't see ever going back to a carb, especially with a turbo and methanol injection.