Back in the 70s and 80s I worked as a tech at a Ford dealership in SoCal. I specialized in TuneUp, electrical, electronic & electronic engine control, emission control, turbocharging systems. I was in that initial generation that watched=, and worked with, the transition from points and condenser electrical ignition, to electronic ignition, to electronic engine control (computerized EEC I and EEC II), and the Variable Venturi 2700 & 7200 carburetors.
Although I felt Ford could have done a better job with the earlier versions of Electronic Ignition and Electronic Engine control with on board diagnostics and memory, which they finally migrated to, all in all I was a fan of the new solutions. When the systems worked well they worked really well. But, when there was a problem, especially an intermittent problem, things could become a nightmare really fast. The "special testing equipment" Ford required dealers to purchase were a bit too far on the side of worthless for troubleshooting an intermittent problem. Back then Ford said diagnostic time was included in component replacement time, and it was not unusual for me to end up tracing down the cause of an issue for a few hours only to be paid 0.4 hours, 24 minutes) for the repair to a bad wiring problem caused a wire not being properly seated into a connector that was buried up inside the instrument panel. Or 0.5 of an hour to replace an ignition module that was failing intermittently, where the problem could only be duplicated after driving the car for at least 25 minutes (and the replacement being verified as having corrected the problem with another half hour or more of driving. We had no portable plug-in OBD1/OBD2 testers, and our analog scopes were large, bulky systems that were not able to be connected to a vehicle while going out for a shake-down or confirmation road test. I had ways I devised to use our large scopes to diagnose various EEC component electrical signals, but back then that was a "black art" and quite frustratingly frowned upon by our factory reps as they told our dealer and service manager that we should be using authorized ways of diagnosing problems, as opposed to our "hack approach" in diagnosing and fixing problems. Therefore, because I was not using the all but worthless authorized equipment they would not pay "M Time" for the time it took to track down and repair unusual situations. As I understand it, a lot of the warranty cost containment approaches to minimize labor time, even clearly legitimate labor time, billings have been largely corrected via various state labor board oversight, the manufacturers still have their labor costs for warranty repairs by having technicians subsidize the labor costs via inadequate labor operation time allowances for the many OpCodes used in billing for labor efforts. The difference in Labor Time Allowances can be significant, and back in the day a swing of 25% or more reduction of Labor Time Allowances between the factory Labor Time Guide and the non-factory Labor Time Guides was not unusual.
So what does this to do with carb vs EFI? Well, despite the advances in the ability to diagnose many computerized issues with OBD1/OBD2 memory and Trouble Codes, many folks in the repair industry will be quick to say that although being helpful, sometimes it takes more than scanning trouble codes to get to the root of a problem. And, even with our portable digital scopes that can be used to test circuits on the fly while driving, often those experiences can still be very time consuming. When I look at the aftermarket EFI systems I often wonder if they have ODB2 scanning capability, or at least the various wave form patterns for their various devices so one can use a modern digital scope to track down a problem. I am willing to let the folks more in touch with those diagnostic issues to chime in as I have never installed or worked on an aftermarket EFI system. But, unless and until I begin to hear how modern equipment can be used in a practical way to diagnose aftermarket EFI system problems I will be sticking to the conventional carburetor, and even electrical old school ignition systems.
The reality for me is that I do not race our 49+ year old pony cars, on the track or on the street. Sure, I enjoy blowing out the carbon once in a while, and do not drive then like an old granny might. It is rare I spin an engine higher than 5,000 RPM, largely because all of our engines are original built, not rebuilt, and despite being in good condition I am not looking to start trouble by floating their valves at sustained high RPMs. Also, when it comes to outright performance it has been shown time and again that fuel injection, much EFI, does not provide any kind of significant horsepower improvement unto itself. Even electronic ignition will not provide more power unto itself. It takes a very involved, well tuned, set of systems and sub-systems for a computerized engine control system to bring fourth performance, much less fuel mileage, benefit. And, I, for one, am not inclined to swap in an EFI system, even with an electronic ignition sub-system, into an older, first generation pony car - especially when there are concerns for how challenging these systems are to troubleshoot. Much less the viability to work with the manufacturer with a repair process, especially a warranty procedure. Removing the components and shipping them to a manufacturer so they can "look at it" within a few weeks is not my idea of a good time. Especially if a manufacturer comes back with a "No Problem Found" response. I have been burned a few times too many by oem manufacturers to be willing to subject myself to a similar situation with aftermarket manufacturers' EFI solutions. They are so quick to point out how easy it is to install their systems (it is never as easy as they claim), and tout their support (try getting parts for their older, now outdated systems some time, good luck), and how easy it is to troubleshoot a problem if one is to occur (they are computerized after all!). I do not trust the phookers. When I read some of the horror stories about folks who have run into a problem with their system, especially a model system that is no longer being sold or supported, I just become all the more entrenched into my position of not introducing a modern EFI, or even electronic ignition system, to a vehicle that is running perfectly well using old school systems and solutions. There simply is not enough margin in it for me.
Now, there is one significant consideration that may cause me to sway my opinion on the matter. If a person has an older vehicle, say a work truck, that has not been replaced with a newer, modern truck, that is used to go between higher and lower altitudes constantly - that kind of situation would benefit from a system that alters the air/fuel ratio between the higher and lower altitudes. But, even then I would be asking why the older truck is still being used like that.
All that said, for those who prefer to lean toward the aftermarket EFI and electronic ignition systems, so be it. I will never gripe about your choice to do so. When you run into a problem with the system(s), especially if your new system is more than a few short years old, be prepared to get some schooling. Lest anyone feel I am taking my position because I fear newer technology, please keep in mind that I lived through the Years of Transition in the 70s and 80s. I do trust the technology when things are working well. It is more that I do not trust the manufacturers (oem or aftermarket) to do what is right when things do go wrong. I do not like being the one to end up grabbing the dirty end of a stick when a problem comes up - especially when it is a totally avoidable problem.