Denon DL-160 v. Grado Gold cartridge??

I have a nice mid/high end solid-state & digital system that I have acquired (due to cost) over a few years. I have recently re-discovered the thrill of vinyl. I was able to buy a new, unopened Denon DP-47f turntable from (best guess) the late '80s. A serviceman bought it in Japan, and never opened it. It was a model designed for the UK market, and came with a DL-80 mc cartridge. Vinyl is fantastic!! I was told by a very knowlegeable audiophile that I should probably change the cartridge, as cartridges lose some of their dynamics after 3 years, whether used or not. Don't know if this is true, but on the basis that it is I'm shopping for a low price cartridge with stellar performance. Shocker, huh? My research suggests that two of the best are the Denon DL-160mc and the Grado Premium Gold mm. Any thoughts on these or other similarly priced cartridges?