For the exact reason that others don't want their kids to see it, I think it's essential for kids to see this show.
Why? Every time the show comes on, my six year old says "They just call her ugly betty, but really she's beautiful!" This show, more than most others on the tv today, can teach tolerance. No matter what others do, Betty stays true to herself, and affects those around her in a positive way. She doesn't care if you're gay, black, white, hispanic, male, female, transvestite (one character had a sex change!), she will still, ALWAYS, give you more than a second chance.
My daughter and I watch the show together. It gives us a chance to talk about things on her level. Last night, when Daniel "lost" to his sister, he went to a bar to drink. My daughter was able to voice her opinions of drinking, and we were able to talk about the reasons the character was drinking, and what has changed to the character to make him think he needed to do that again. When his brother returned from the "dead" as a woman, it gave us an opportunity to talk about different people and the mean ways that some people treat others in this world.
All in all, a great show that helps teach social tolerance on a level that no one else has managed to do before!