TheTechLounge published a Sapphire Radeon HD 3870 X2 review.

Quote from the review: "So why not just get two 3870s and rub a little CrossFire into your box? There are two reasons, really. For most people, that's just not an option. Dual-PCI-Express can easily tag a Benjamin onto the price of a motherboard, and, in Micro-ATX land, it's a mythical beast that visits overclockers in their dreams.
And there's another thing: regular 3870s get the lower-binned GPUs--the faster-clocking chips go into the X2s. But, lastly, the 3870 promises something else: tri- and quad-CrossFireX. But that begs the initial question: now that the release is behind us, how much awesome stuck to the HD 3870 X2, and how much washed away?"
Read the full review on TheTechLounge.