Which method you prefer?fat model or thin model?

Definitely fat models, although I realise this practise is not set in stone.

When you've got a lot of business logic in your controllers although it helps because you don't have to keep switching to different php files it actually makes it more easier for bugs to creep in.

Let's say you have two controllers which do the same thing, you would have to make sure any business logic in each controller is identical. If you move all the business logic into the model you only have one place to look for potential bugs.

This may not seem like much on small apps but when you start using 10's if not 100's of controllers you soon realise the benefit.

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