dvd media

What is the difference between DVD-R and DVD+R? I was told that DVD-R is the best way to burn, but I am ignorant to this so I want to know what is best so I don’t end up with a bunch of coasters! I have a Sony DRX510ul burner and want to burn about 200 VHS tapes to DVD, and was also told that Ritek is the best media, although some are cheaper. Can someone detail this for me?
Thanks,
Dave