Actually, I am an enthusiast and I prefer the MicroATX format. Is it a challenge to build a fast, quiet, powerful system with full ATX? No, not really. Is it a challenge to do the same with MicroATX? Yeah, at least a bit more. I don't give up ONE THING by using MicroATX (but then, I don't have or need a full-SCSI dual processor rig), and what I do get is more space.
Mark my words, MicroATX and other small form factors are becoming more and more relevant, and mush as cooling, overclocking, and case modding have been the recent fads, the next fad is small, powerful PC's.
Pete