The ASUS M3A78-EM is an excellent value in a mobo for AMD AM2+ systems, and a great performer. I have 2 of these and 3 intel machines, for audio and multimedia development. The AMD phenom II gear is just an awesome value for the money, and a great performer. I am especially happy with the Phenom II x2/545/ASUS M3A78-EM/ 1066-ddr2 combo! It easily performs on a par with Intel ddr3 machines that cost 3 times as much.
I have the ASUS M3A78-EM mobo and a phenom II X4 940 BE 3.0 and it rocks! I installed an aftermarket cpu cooler, but it only overclocks to 3.5 ghz. I can run it at 3.6 ghz, but it'll crash if I try to run Prime95 stress test. I'm perfectly content with 3.5 ghz, it runs all my games at 60fps or better!