Which turntable should I keep?

After inheriting much of my Dad's classical and jazz lp collection, I've decided to rekindle my interest in vinyl. So I've pulled my old Thorens TD 145 out of storage (Stanton 681EEE) and found the box with the $10 garage sale Denon DP-51F that I bought just as it was about to find its way to the landfill. I haven't kept up with turntable and cartridge developments for the last 20 years, so I'm not sure which of these to use, or if I should buy new? The Stanton has about 7 years of moderate use on it, so I don't know if I need to replace the stylus. I've googled both of the turntables, and haven't learned much except that it seems that I should have ponied up for the TD 160 way back when. Haven't seen much on that Denon model, so I don't know if it is low or mid range equipment. I know that I've been pretty gentle with the Thorens, but don't know anything about how the Denon was treated. Its cartridge is a tan Grado with the marking GF 1? on its front. Any suggestions on what I should do? Modifications, upgrades, new purchase? Which cartridge is the keeper? Or should I buy new?