I just got a no-name brand. It works fine.
It'* not too hard to install. I had my dad do it since he is a mechanic, but I watched. Bascially do it when the engine is cold. Take off the coolant hose by the throttle body, and take out the old thermostat and gasket. Put the new gasket with some sealer on, and put the new T-stat in as well. Then put everything back together. You may want to add more coolant if you spilled some.
I know this isn't too detailed, but maybe others here can help out some more.