Soleron on 22 January 2009
It depends on the price point and the applications you intend to run. Intel'd quad-cores are faster but the Phenom 9850s are generally cheaper and will run most things as fast as you need.
Also, the Phenom 9850 has been replaced by the new Phenom II which is much faster and offers real competition to Intel. If you can get a Phenom II, they are better value than the Intel quad-cores at the same price. Finally, AMD motherboards tend to be cheaper so consider the whole PC cost.
For a mainstream quad-core, I would probably recommend the Phenom II X4 920 at $195. It is cheaper than the similarly-performing Core 2 Quad Q9300 at $250, and faster than its competition the Core 2 Quad Q8300 at $195.
