The SPx is a really good product, I've had 4 boxes.
On average, meant to have
2 RC Auto GU's
2 Dual Game Worn (Winning Combos and Winning Materials)
1 Rookie (a non-auto/GU version)
1 Throwback (could be lucky and get 2)
Not bad really, cant argue with that.
Can usually pick up for about $85-$95USD ex Shipping.
Dont know much about the SP Sig Tins, but meant to have 1 Auto per Tin, but odds of getting something decent is slim from what I've seen/heard.
If you're after an SP Sig tin, go for the 04/05 Edition, because the 03/04 tins go for almost double the price. I picked up an 04/05 Tin for $40 on US eBay. Waiting for it to turn up this week.