Oddly enough, people with good judgment are not usually considered judgmental. Judgmental is a negative word to describe someone who often rushes to judgment without reason.
The adjective judgmental describes someone who forms lots of opinions — usually harsh or critical ones — about lots of people. Judgmental types are not open-minded or easygoing. Judgmental has the word judge at its root, which itself is from the Latin word judicem, which also means "to judge." Judgemental (with an extra "e") is considered a legitimate variant spelling of judgmental.