Absolutely nothing.

(I've been wondering when the subject would turn to reels because with die-hard pinners it always does.)

For the most part there aren't any bad pin reels made. If they don't do the job and do it well, they don't sell period. That isn't to say there aren't differences, but it's like watches, where a Timex might keep just as good of time as a Rolex, but you'll definitely know the difference when you wear them. The good news however is that the price difference between the entry level reel and the high end reel is not nearly as much as in watches.

This is because the CP reel market is very limited and fabrication demands precision machining, thus prices start relatively high even on entry level reels. On the other hand, these factors, combined with simplicity of design, also allow smaller custom fabricators to be very competitive too.

Entry level reels like the Okuma and Raven are production reels made in Asia to reduce cost and maintain quality. Higher end production reels like Islander, Ross, JW Young, Hardy and Kingpin are made in NA or England and are a bit more expensive as you would expect. Custom makers like Milner, Paine Falls and River Keeper are selling all they can produce at prices similar to premium production reels.

Resale is very good on high end production and custom reels; but not so much with entry level reels. Also due to longevity, quality and collectability, "out of production" reels like Hardy, Mykiss, Hanson, Coulson and MacDonald are still sought after and fished too.

Our NW rivers generally don't demand the same precision that Mid-west or Eastern frog water fisherman demand in their reels, so any decent CP reel will suffice nicely out here. But if you become dedicated pinner you'll quickly appreciate the finer differences and wish you had bought up early, especially when you consider resale. The best advice I can give to anyone fishing with a nice entry level CP reel, is think twice before trying out your buddies new production Kingpin or that ol' codgers custom Milner.