I have to say that the only thing I don't like about my lvl 26 Vanguard shield spec is that his armor pieces don't match. He's got mismatched color going on everywhere. Other than that, I can take on some tough mobs and only a few of them give me trouble. I also like how you get to learn tanking a bit by keeping the mobs off your healer companion. For somebody like me who's always played DPS in previous MMOs, that's particularly helpful.
I did watch some Jedi tear into a mob I was struggling with though, it was like watching someone rip up tissue paper. But hey, he was DPS, I'm a tank!