In my opinion Teacapan offers the best beach experience I've ever encountered. We started in 1999 at the Rancho Los Angelos north of the Onac. It closed in the early 2000's and we then camped at the Onac - which was fairly busy so the owners usually put us on a site near the south boundary which we liked. Then the RVers disappeared - first the US ones, then the Canadian RVers. It's a shame.
Not sure what the deal is with currency exchange - Canadians get whacked with a very low rate that doesn't match USD exchange even when taking into account the USD/CND rates the US gives. It's always been like this and has always been a bone of contention for Canadians.
I recall the early days standing in a long line at a bank in Escuinapa with a handful of traveler's checks to buy pesos with... It's so much easier now with ATMs.
Also easier - internet access, calling home, watching movies at night. T-Mobile works great in Mexico, better than back home actually. 5 gigs of data per month are allowed and then the data is slowed but still allows watching Prime or Netflix with hardly any buffering. Sirius works again in Sinaloa and points north. The satellite is still positioned south rather than overhead (I can tell going under bridges) but Sirius must mask the broadcast shadow like DirecTV did.