If find the wind predictions from Swell Info to be fairly accurate, but like any weather prediction, its about knowing your spot, putting your own eyes on it. Far to often the surf sucks or gets ridiculously good when quite the opposite is being predicted. I also find the local news to be a good place to check for wind predictions.

As to your query about where the predictions come from, everyone is right, different surf prediction services use different weather services and even buoys or local weather stations. I say again, why not just go look at the surf. If you are not in such a position, local surf shops have call-in reports, you can view cams, or you can use marine forecasts when making a decision to drive to the surf. Still, there is no better surf forecast for a given day in question then your own two eyes. Everything else is just a tool to give a general idea of what might happen, and they are all wrong often enough to never completely trust.

Equally, when the wind is blowing and the swell is right, its about knowing your local surf zone and multiple spots. No swell forecast service can beat this most useful of predictors.