Can't speak to the examples cited, but I've used some Class D amps in automotive installations. They do the job, and pack a pot of bang per pound - they are exceedingly compact - but in terms of fidelity, not anywhere near the capabilities of an old Sansui (or any number of other brands of the era).
I chose class D for that application, due to the compactness and efficiency, less so for the sound quality which is decent enough. Been happy enough with that decision, but would love to have some Sansui power in the car with me. Regrettably that's not so easy to do, nor is it practical.