"What's the best...?" How many times have a seen this question asked and answered. The trouble is the answer is usually wrong. And why is that? Because the question is too imprecise to answer correctly.
First let's define "best" According to the Merriam-Webster online dictionary "best" can be defined two ways - "excelling all others" and "most productive of good - offering or producing the greatest advantage, utility, or satisfaction." Both of these definitions rely on being able to quantify or at least define a set of criteria for "best." In the world of audio these criteria are not fixed or definitive, but vary depending on each audiophile's physical circumstances and aesthetic tastes.
A practical example of how "best" could be different for two audiophiles with very similar systems, but differently-sized rooms: audiophile one has a large room with medium/high efficiency speakers who like to play rock music at near-concert levels while audiophile two has a small room with those same spakers, and listens primarily to chamber music and jazz. For the first audiophile a powerful Krell, Classe, or, Pass power amp would be in the running for best, while for the second audiophile one of several single-ended tube triode amplifiers would be more appropriate for the role of "best."
Because an audio system is, by definition, a SYSTEM, that requires a host of different components needed to work together, the concept that any particular component can be universally better than all the other possibilities is absurd. Give me a component, any component, and no matter how universally praised, with a bit of time I can probably figure out how to put it into a system where it will not be the best option and could actually sound quite bad.
So the next time you hear that a particular audio component is "the best," please add in the bolder-sized grain of salt that such a statement deserves...