Totally agree. This is a very nice choice for a MDD. Not only is it simply faster with a wider and faster memory bus, but unlike the Radeon 9000, it will provide you with hardware acceleration for Core Image under Leopard, further improving overall performance.
Gorgeous Quartz Extreme rendering and very smooth OpenGL. Very nice card and $60 is a very very good value.
Of course, this card will produce more heat than your Radeon 9000 and the AGP is positioned such that the card's fan will be sending that heat to your CPU's heatsink. This makes CHUD even more important. I currently have two MDD dual 1.42's--One with a Radeon 9800 Pro and one with a Radeon 9700 Pro. On both of mine, I installed an extra fan between the heatsink and the back case. It's positioned high enough to immediatly vent any heat generated by the Radeon, but it also helps pull cool air across the heatsink.
If I ever redo it, I'll use two fans similar to what this
person did. For now, though, the single extra fan combined with CHUD keeps my temp well below any cause for concern. The biggest difference came with CHUD.