I've beaten the game before, and bought in on Steam just to re-live those days. Plants Vs. Zombies has been one of the only Tower Defense games that I give a higher rating than 7.
The Plants and Zombies are well thought out and creative ideas with some humor in them. The game is balanced(until those damn Yeti Zombies). And for the Genre, the final boss battle does require strategy in order to beat him(which many games just have you slash away without thinking.)
Anyways, overall I feel this game deserves a 8.5/10
But it gets this rating for a few reasons, here are a couple.
For starters, the game is sort of a begineer's trap, a few waves and the bucket zombies are already causing a ruckus, another reason is because some of the plants are a bit too strong(as well as some zombies). For instance, the minigun Pea Shooter, that thing is a ♥♥♥♥ing monster. And for zombies, the snatcher(I can't remember what it is called.) They have been a reason I have lost many of times, and there is not to many ways to avoid them, it is only if the plant they try to snatch is a chomper, or a minigun peashooter. Rather than that, it's a done deal.
Anyways, that was my personal review on PvZ and I defenitly do recommend to anybody. Buy this game, if you are a tower defense fan.