The Newegg offer is going to cost you $380 + $7 ship. for $387.
The Tiger offer will cost you $390 up front and you'll wait a long time for the $30 rebate. And their rebates come in the form of a pre-paid debit card.
So, there's not much difference in up front costs. If I were buying, I'd probably opt for the Sapphire. Because you mention over clocking, and the Sapphire looks to have a more robust cooler with better heat pipes, I would say go for it.