the 2100 is cheaper because it's SS yes, but also because it is the 'utility' version. Same model as the ones with the big blue meters (2105), just a different case. Also, the 2100 has a set of inputs and built in volume controls so one can plug straight in with a line level source. no need for a preamp. I used it that way for years. I'm telling you, that amp, a cd player and a set of ADS speakers and you have a killer stereo for $800. My fav ADS are the l520 and l570. They can be found on craiglist for $100 or so. The are both 2 way med size acoustic suspension 'new england' style (AR, boston acoustics etc) except they use german made drivers so they have a new england sound but with more of a german flavor, i.e. tighter, cleaner, more high end. Can be a little analytical but when paired with the mac, they are just about right.
