For me, the most noticeable differences are between Spain, Mexico and Argentina.
The speakers in Spain use the “th” sound in place of “ss” sound. For example, they say BarTHelona instead of BarSSelona. Yes, it is spelled Barcelona with a “C”.
The Mexicans speak Spanish with lazy sounding syllables.
And The Argentinians speak with a very distinct dialect. It would be equivalent to the way snobbish New Englanders speak English.
Agreed. And sometimes the differences are subtle.
To add the Colombian dialect though, I see now (or hear now rather) why it has the reputation of being the prettiest sounding.