I think Sal Buscema is the most under rated. He has many detractors but he had such a huge body of work- mainly because he was fast- but you can't knock that! But he was a great story teller and his action sequences were great! I always look forward to reading a book drawn by him. In fact, he's one of my top 5 favorite artists. Not to say I think he's one of the top 5 BEST artists, just one of my personal favorites.

I think Neal Adams is the most over rated. He's a dynamic artist, but he doesn't blow me away.

As for the best from the SA, you can't argue with jack Kirby for everything he accomplished, but my personal favorite is John Romita