Well after working with mgb's for a number of hears, I do think SU carburetors are undesestimated, especially the later model HIF bottom bowl, temperature compensated ones.
I think its probably because they tend to last past their optimum tune life and develop worn shafts, ets which dont cause catestrophic failures , just annoyances and that folks dont take the time to tune them properly.
The last MGB I had in los angeles was redone in 2002 with HIF s and they ran fine till i sold it in 2014 when I moved to texas. The only routine maintenance/tuning I did was to wipe the dust out of the bores every 2 years or so.
Idle adjustment didnt seem to need any attention once it was done initially.