A professional mix that's distributed to the public has to sound good on the various different systems it may be played on, so professional mixers monitor on good speakers, properly arranged for stereo imaging, and also check the mix on other systems -- smaller speakers, bigger speakers, crappy speakers, headphones, earbuds, etc -- to make sure it works on many different systems. They also try to mix in a room that doesn't overly color the sound.
Most likely anything you hear on the radio will have been mixed and mastered to this standard, so while mixes all sound a little different in tonal balance and dynamics, they all should be up to certain standards of what's considered professional quality. That said, those standards -- and mixing preferences -- change over the years, so 70's songs have a different sound than 80's songs, etc etc.
If you plan to market your music then you would need to pay some attention to how your mixes sound compared with other commercial mixes. Or you could have them mastered professionally -- part of a dedicated mastering engineer's job is to make sure a mix meets current professional standards. On the other hand, if you're just distributing your mixes casually, or to friends & family, then that's not so important and I wouldn't really worry about it at this point.