There are certainly benefits and drawbacks to each choice.
I would love to get a good 750 Commando again. Would I try to ride it daily as transport? No. Way too much of a PITA; modern bikes work a hell of a lot better. And the Commando is one of the more usable and functional of vintage bikes.
I really like my Monster M900. I think it hits a sweet spot in bike tech -- it is modern enough to be reliable and made with modern materials and manufacturing tech, so it is durable and mostly trouble-free, yet old enough to be simple and repairable. Yes, it has carbs, but they are good advanced carbs, and have not caused much trouble; they start in cold weather and all that. It is quite likely I will be riding it for a long time yet.
However, if I did need to replace it for some reason, I would be happy to move to a new bike with FI and ABS and all the goodies that modern tech entails. It will no longer be repairable by me with handtools, yet it will work well and long and not take very much attention either.
It's all trade-offs.
1993 Ducati M900 Monster "Patina" (220,000 miles, so far) -- 1995 Ducati M900 (wife's bike) -- 1972 Honda CB450 (daughter's bike) -- 1979 Vespa P200 (daughter's scoot) -- 1967 Alfa Romeo GT Jr. (1300cc) -- 1964 Vespa GS160 (160cc 2-stroke) -- 1962 Maicoletta scooter (275cc 2-stroke) -- 1960 Heinkel Tourist 103A1 scooter "Elroy" (175cc 4-stroke)