When I was doing research about getting the g-tube, the thing I was most concerned about was lots of complaints about leaking, like Gabrielle. At first, I thought I was going to have that problem, too, but after I spent about 5 months battling granulation tissue around the site, I have very little leakage. I do have a bit of raised scarring that is mildly uncomfortable, but a bit of cream and rotating the tube relieve it quickly.
I don't know if I'm the exception, but the leakage I experience in no way outweighs the benefits I've gotten from the extra calories. As mander31880 says, it's nice to look a bit more your age instead of looking 9 years old in high school. After all, that extra 10 pounds translates into extra curves, making you look more mature.