ASUS has done a wonderful job with the A8R-MVP motherboard. The board came with all the features, performance and bundle that you want from a Crossfire motherboard today. The features chart shows the A8R-MVP to be among the highest feature-rich motherboards around today.
Crossfire worked as advertised in most cases. One thing I noticed with the Crossfire motherboard is that the board was a bit flaky with the shunt card installed. With the regular x1800xt installed in the blue PCI Express x16 slot and the shunt card installed the system would not boot to video. After a lot of consternation and experimentation, it turns out the shunt card needs to be removed to operate and the CMOS needs to be cleared to operate after.
Dual card solutions have advantages and disadvantages over single card solutions. The advantages include better performance in games that take advantage of the dual cards, better image quality and bragging rights. The disadvantages include: the extra cost of dual cards (up to $1300), the extra power required by the video cards (two extra power connectors are required), the fact that something better is always coming, and the ever-increasing pace of video card releases.