So far your experience is the EFI is more reliable than the engine? I bought an HF pressure washer with single carb (after some doubts). After 1 year the major issue is starting. The thing wants choke to restart hot, possibly because of the cold water pump bolted on. Probably shouldn't say this but despite the starting issue and couple awkwardly located oil drain and check ports, a powerful devil .
I haven't had it long enough to comment specifically on the EFI but Cub Cadet introduced this engine a couple years ago in the XT2 (more expensive model) and now are offering it in XT1, as well as on a twin cylinder. It's a system designed by Walbro and they have decades of EFI experience. My bad luck with the Cub engine itself seems unusual - the people at the Cub dealer all were familiar with how 'blowed up' my tractor's engine was. It obviously had a major defect from the start. If there was a problem with the basic design, after 2 or 3 years I am sure CC would have ironed it out.
https://todaysmower.com/walbro-worked-with-cub-cadet-to-launch-the-first-consumer-efi-lawn-tractor/
Everything I've ever owned with EFI has run beautifully. I can't say which vehicle was the worst running of those because none has been anything but perfect in all temps, hot starts, idling, frigid temps, they just RUN. The very idea of a 'remote starter' back in the carburetor days would have been somewhere between iffy and crazy. Now, you press a key fob button at 20 below from inside your house and your car starts up. Those of us who grew up with carb'd cars and trucks know that even for a new car, back then 20 below gave you no more than a 50% chance the engine would actually start.
I've got a pressure washer with (of course) a carburetor and for the most part it runs fine. I'm not saying a carb'd engine can't or won't run well but with my pressure washer I still have to twiddle with the choke control sometimes to make it run right even when it's warmed up.