Mostly just a matter of geographical proximity for me, but I like Sazon Cuban Cuisine on Collins Ave. in the 70s and Moises Bakery across the street for Venezuelan baked goods.
OLA in South Beach would not qualify as "traditional" nor would Tuyo, which has Latin American influences among many others.
If you search this board you will find plenty of info on Cuban restaurants, i.e. ->
If you stick with the Venezuelan choices in the menu, the best Venezuelan I've found so far is Brasero's (locations in Doral & Weston - never personally tried the Weston location). Supposedly when they have live music at night, it becomes popular. I would call in advance. But beware, I was not impressed with the non-Venezuelan choices in the menu. If you're just looking for Venezuelan arepas and standard street food arepas, my favorite is La Latina in Midtown Miami - they're also open late at night. Another late night Venezuelan spot that's popular is Doggi's & More near Brickell in Miami, but I find the arepas and prices better at La Latina.
For Latin food in general, I'd recommend either OLA in South Beach or Tuyo in Downtown Miami for noteworthy stops - and they'll be better than any other Latin-specific restaurant recommendations, including the Venezuelan ones I mentioned above. I also love Catharsis in Little Havana's Calle Ocho which is pan-Latino (with maybe a strong Argentine influence).