Just to add another opinion here, my experience is that the Fraunhofer encoder is the best at a fixed bit rate, with the Xing and then the BladeEnc following behind. At low bit rates (32K, 24K), the difference is obvious (as to why I'm encoding at those rates, that's another story). Xing's VBR encoding is better for a particular size of file because more complex blocks are being encoded at higher bit rates. MPEG audio was in part designed for specific bandwidth streams where it's easier to guarantee a certain speed of transfer rather than deal with lumps of high speed and lumps of low.

Feed the Hungry. Save the Whales. Free the Mallocs.