Brother HL Series - Same Print Engine?

[machineage]

Hi

I just wondered if anyone might know whether the recent HL series of Brother Printers use the same print engine? They appear to have the same print specs - but reviews seem to differ in terms of their print quality?

I am specifically looking at the HL-5350 / 5380 / 5370

I am also looking at earlier models too - namely HL-5250 / 5270 and assumed they would have a different print engine.

Thanks!

M.