Is it worth purchasing one of the other non sony controllers? Which ones do the same things as the dualshock controlers? I've heard the Logitech Cordless Action Controllers are awsome so has anyone ever used one of them?

the logitech wireless one is awesome, used to have one but sold my PS2 but it was comfortable to hold. I also picked up a couple no name controllers. They came with dark cloud 2 and wild arms 3. solid ps 2 controllers and for 18.99 game included can't beat the price. It really all depends on your personal preferance. Aftermarket controlers generaly have one or two features that have either been upgraded or are missing on the standard PlayStation 2 controlers. (IE Ergonomics, buttons positioned in better positions, rumble packs)

the logitech are cool

You should probably just stick with a regualr sony controller. the third party ones have issues