When buying carpet for your home I've found through years of cleaning and installation that Nylon carpet , with at least a 6 lb. carpet pad , will clean & wear the best over 10- 15 years of use.
Polyester carpet does not clean nearly as well and is subject to
shading wear ,a condition which the carpet fibers will set one way
in random waves ,giving a dark-light hue that gives the appearance of dirt.
Carpet density is key in the life of the carpet regardless of style
(plush, berber, level loop ) ,along with a 6lb - 8 lb rebond pad.