The main thing that the Conroes have over AMD is their better, more efficient architecture. Before, a Athlon 64 only had to have a speed of 1.0Ghz to keep up with a 1.6Ghz Pentium 4. Now, a Conroe only has to have a speed of 1.0Ghz to keep up with a 1.33Ghz Athlon 64.
That, and the price. A $244 2.13Ghz Conroe E6400 is like a $1010 2.8GHz Athlon 64 FX-62.