There was an ebay coupon code recently where a buyer would save up to $100 on a $500 purchase, so I decided the time was right to grab up a pretty nice Mantle. In the end, I was down to looking at 1964 cards graded 7 by both PSA and SGC.
If I recall correctly, the SGC was priced at about $470 and the lowest PSA one was $625, with most being at $675 and way above that. If you look at these two cards, they have very similar top-to-bottom centering and the corners of the SGC card are much sharper overall.
1964mantlepsasgc.jpg
To me it was absolutely worth it going with SGC and paying a minimum of $150 less for the card. When the time comes to sell him in the future, though, I will have to figure things out to get a better return like you seemingly always get with PSA cards.