best fan option out there?

That's a great deal. I myself would probably opt to get the new clutch, just to avoid the possibility of a bad/worn clutch. I got mine (Hayden 2765) for like $41.00 I think.

Not really sure how to test one on the fly. Should spin when it's cold though and lock up more when the front spring coil on it gets hotter.

With some resistance. If you spin it and it doesn't stop itself, the clutch is bad.