As far as factory systems go it is great. My dad has a Bose system in his Vette and he made a comment on how mine sounded much better. Now for very little money you can gut the Mach system and go completely aftermarket. I have a Kenwood inexpensive head unit, two 6.5 inch dual cone door spearkers and two 5.5 inch two ways in the rear side panels and a Bazooka amplified base tube in the trunk of my Probe and it sounds every bit as good as the Mach in my Mustang. Total price was 300 bucks.
The Mach is a good system. The base is pretty good but not stomach upsetting. I have a Nelly CD (extent of my hip hop collection) and the base is tight. I especially like the intro to Enter Sandman by Metallica...it kicks pretty good on this system.