Nobody regards FT to be in the same category as either AITF or TDDUP.
Now if you want to compare Sanford and Son with Steptoe and Son . . . (the US version had fewer seasons in this case; and I did see both)
Actually, as a Brit, I think Fawlty and Till Death are two of the greatest sitcoms of all time. Till Death is rightly regarded in the UK as one of the all time classics. Right up with Fawlty Towers.
As a Brit, I admire the US version, it stands up on its own, possibly the only UK to US sitcom transfer that does.
I have no wish to compare the ‘and Son’ versions. As comparing the Redd Foxx version to the BBC original is like comparing a cheap tasting 99c hamburger to a meal in a five star restaurant. I have seen both, and the original is as great a sitcom as was ever made. I thought the US version was crap.
I am not being the snobby Brit btw, I can think of howlingly bad UK versions of great US sitcoms. The UK versions of Married with Children and the Golden Girls for example were truly awful.