I have not attended any Napa classes and only 1 Snapon class, wasn't impressed. But Worldpac training is really good as well as Carquest CTI. But also checkout BWD training through Orielly's. It is pretty good, especially for those that haven't had much training. Also ATG has awesome classes, atgtraining.com You can sign up to be notified of any upcoming classes that aren't on there website yet. Also for a multi day training expo there is Automechanika in Atlanta August 8-10. ASTE in Cary, NC the last Fraiday and Saturday in September.
You should also check out scannerdanner.com You can get his book for $100 and his premium content for $11/month. His premium content with his book is worth so much more than he charges. His premium channel used to be on YouTube but it is now on his website. I can't recommend that enough.