I’m familiar with both combinations (and indeed, still own some sets of the 42/110) but have never done a head to head comparison.
I recall that @Adam.Meredith has a lovely Naim restored NAC22 and NAP120 so he could probably give you further insight as to performance.
The NAC22 was introduced in 1976 (the NAC42 in late '79) and was less sophisticated than the NAC12 and designed to be a more affordable offering, with high level circuitry on the main board and plug-in phono boards (NA222s at the beginning, then NA322s from '77 onwards).
I was told that the NAP120 came about from a still-born active speaker project for someone else, where Naim were to build and supply the internal amplifcation. It’s why the first series of NAP120 looked pretty rudimentary and inside used a laminated transformer. Later NAP120s had improved casework and a toroidal transformer.
Both the NAC22 and the NAP120 were replaced by the NAC42 and NAP110 in 1979. Note that these first 42/110s were in a shorter chassis and extruded case than the later ones, but not quite as short as the upcoming NAIT.