Developing 2D games in Unity

I know by looking at the title you might think it is a very common question. Well actually my question is more like which is the best way to develop 2D game in Unity? Should I use SpriteManager2 or just making a flat plane and put texture on it?

What If I want to run sprite animation? Besides, how the performance gonna be if I just use a flat plane with texture? Does Unity do dynamic batching to optimize it?

We have had a lot success with 2D Toolkit for general 2D needs including animation. Unity has native support for both dynamic and static batching.