This is very true and illustrates how awesome this game is for flight characteristics variety!
It also makes it a bit annoying when apparently everything below 300 is considered slow when the average small ship speed is 250-350 with 4 pips to engines (between E-A modules).
Everything else demands engineering and high performance engines.
So instead I would say anything above 250 with 2 pips to engines is NORMAL while anything above 350 with 2 PIP's to ENG is FAST while anything above 500 with 2 PIP's to ENG is LUDICROUS and reserved for racing or the extreme outliers of iCourier fittings.
And those with 600+ are going to the Spaceballs category of PLAID speed.