I ride a Specialized 29'er Stump Jumper Comp which is aluminum. I'm not a hard core mtb guy but have done a few races and TT's and have also used the bike in cross races, single track and in the snow. For the type of riding I do a FS bike is not needed. When on single track I can blast over logs, rocks and any thing else in the way without much difficulty. I just love riding over things.
The knee wound in the image was not the result of a crash. My brother in law passed me on the outside of a tight turn then cut down on me causing me to fall.