If you're into moe girls and military hardware, this anime is a must-watch!
It holds up on its own, although you may not find it exceptional. The plot provides just enough character development to get you invested in the heroines, then switches to dynamic action sequences to produce tension.
What makes this a true gem, however, is how realistically the tanks are portrayed (outside the odds of surviving a crippling hit if you're in one, that is). The tanks move like real tanks, not slow and ponderous like the stereotype but fast enough for Blitzkrieg. They shoot like real tanks, with hand-loaded shells, proper military sights, and rangefinding done with mental arithmetic involving the target's actual and apparent sizes. They even suffer from real-life limitations, such as engine malfunctions, bogging in rough/muddy terrain, track breakages, and lack of penetrating power affecting tactics on the fly. (Fuel and ammo limitations are also brought up, but never directly affect events.) The only unrealistic part would be the severe lack of efficiency in which the tanks are used, although the pilots can probably be excused for that, given that they're high schoolers. (Real-life tank battles are a lot less glamorous anyways, being mostly fought from ranges of 500m or more.)
Of course, no anime is for everyone. If you don't find the combat scenes captivating, then you probably won't get much out the show as a whole. All developments outside of combat are aimed at making the combat more intense through personal investment in the characters; while this is a strong point for the show as a whole, it leaves the non-combat portions not substantial enough to be worthwhile on their own. Also, many of the background characters are one-dimensional, which some may find off-putting. (They form small groups of 3-6 which are *very* distinct from each other, each being the crew for a separate tank, though there's less variety among the members of each crew.)
