Joe Frazer felt the Manhattan name suggested the up-market area of New York City and in addition to having higher quality interior fabrics, two-tone paint work and a larger standard equipment list, the 4-door Frazer convertibles and the 1951 4-door hardtops were Manhattans. When Frazer production ended at the beginning of November 1950 (YES, I said 1950!) the Manhattan name was moved to Kaisers starting in 1952 as an upper end series.
As a rule, a Frazer may fetch a few hundred dollars more than a Kaiser or even a Kaiser Custom but it depends mostly on what catches someone's eye.