Plants vs Zombies is my favorite game on iPhone. Angry Birds would rank #2. I just love the production values for PvZ better, it was funnier, Crazy Dave rocks, and the ending music video was funny and rewarding. But it was fairly easy as I got all the achievements within a week. I have never lost beating the Final Boss each time and the only hard parts where I had some mild struggle was the levels with the fog. The rooftop was a cinch. Angry Birds has more replay value, but can be frustrating sometimes. Some of the birds like the woodpeckers and toucans could feel so worthless at times in certain levels. My fav birds are the black ones that act like bombs.
I do not plan to update PvZ, and not only because of the crashes I hear about. I want to keep my Michael Jackson zombie for as long as I can! Now if they bring the Zen Garden and more mini-games, then I will consider losing Jacko and better icon.