GT is a whole lot of fun if you just don't think too hard about it and enjoy it for what it is. There are minor inconsistencies here and there, but unless you're the type of fan who's over-obsessed with strength debates, you won't notice MOST of them (some are just too big to ignore, though).

I really enjoy the lighthearted adventure atmosphere of the Dragon Ball hunt through space, and the Baby arc with the last Tsufrian exacting his revenge on the last Saiyans is really the series' high point. But it hits its peak there, and it just gets worse until the end. The Super 17 arc is a total mess, and the Evil Dragons is a great idea that was just executed very poorly.

iv personally always liked dragonball gt, but it was never as good as dragonball & dragonballz. im currently rewatching gt with the japanese score & i have to say it is so much better. watching gt with the japanese score changes my opinion on gt entirely. i once liked it, now i really like it. if you have the gt season sets i recomend you watch it with the japanese soundtrack/score. i may do a review when iv watched them all & give you explicit detail on my opinion. but seriously, dont hate gt, give it a try with the japanese score.

Basically what everyone else said. GT is what it is, but it's hardly a sin against the franchise or anything. I quite like the Super Saiyan 4 design, and the Shadow Dragon arc (despite being poorly executed as Kaboom said) was an ingenious idea. Hell, if you wanted to, you could even say it was hinted at in Z.

GT was the first of the Dragon Ball series that I saw in Japanese (in fact, I saw it in Japanese raw on the International Channel before I ever saw the dub), so dispite its plot holes and repetitiveness, I enjoy it for what it is and it has sentimental value to me.