Over 7 seasons The Shield consistently provides an incredibly diverse group of characters and more intrigue than most TV has ever provided. The web Vic and his team weaves is always winding in all sorts of directions and is often on the verge of breaking. Vic and the rest of the strike team use their authority and cunning to untangle it as best they can, almost always using tactics that are ethically questionable at best.
The whole thing really gets you sucked in and you're always torn because rooting for Vic is easy, facing what he really is is not. What's right and what's wrong? When do the lines begin to blur? It's not always clear, but it's incredibly entertaining to watch.
The other thing I really love about the show is how there's always another separate case being pursued by Dutch Waggenbach and company. It keeps each episode going in different directions and the case is always interesting or has an unexpected twist when it's resolved. I think another thing that separates this show from all the others is that you get your murder/rape case that you get everywhere else, but that only compiles about 30% of each episode and the rest is even better than that. Shows like CSI and Law & Order can't even touch the content this show brings, and I haven't even mentioned the gritty, realistic style it's shot and written in. Absolutely unique and done believably and well. The finale? It's as good as you're ever going to get.
It really is a stellar show. I would say there was perhaps one season I thought was only above average (not exactly a strike against it) but the rest was a thrill ride that was so gripping I don't know if there's more than a handful of other shows that have ever matched it in that capacity. You're always in for a surprise when you watch it and the characters grow on you, some of them whether you want them to or not. Recommended as highly as possible.