peachtree amp vs. traditional amp

OK, I'm a newbie, so this is possibly a dumb question.  I am considering a 2 channel amp to listen to music (Tidal or spotify).  I am looking at a traditional looking black box amp by Yamaha or Marantz.  But I've also seen a very small amp by peachtree.  The peachtree seems to be about the same of watts as the others.  How would the sound compare?  It seems that the peachtree is so small, it would not have the same power.  Doesn't size/weight translate to some level of power?  Anyways, has anyone compared a peachtree to a traditional amp of the same power rating?  Please share thoughts.