Let's leave it at that! Been there, done that and not "downtown/south beach", but in the newest developments south of 8th st and towards the edge of the everglades, by the Eden lakes...
SD just like Miami, has its good parts and bad ones as well. Been plenty of times to Aventura and pretty much everywhere else in Miami. Great city to have fun, just like SD but in dollars... With 24/7 power, water, sewage and plenty of Police from like ten different sources to pick from.
The day SD gets those three, prices for RE there will make Miami look like a poor's man other single option, for a tropical retirement home...
Sadly, Miami concentrated all the major vertical development in the small downtown area, while the rest is as flat as a 10yo girl's chest with freckles all over... SD is growing correctly with maximum dispersion area, while going vertical.
Being the oldest city to develop in the last few years, we're bound to see better infrastructure in SD than other older developed cities around today.
That's what's taking place with the SD Metro for example, since all is new to it, having been built from scratch; the SD Metro is by far the most advanced city rail system in this hemisphere, save none! Even while Venezuela is building some other new lines, the system they opted for was not cutting edge like ours. Same goes for the other Metro lines in Canada and the US, Mexico, Brazil, Chile, etc...
A Metro like the one in SD, would cost billions per km constructed there!
Give SD ten more years of speedy development and things will look much different by them... Give people 24/7 power, water & sewage as well as good Police, and things will get very expensive soon after all over the city.
I lived in Miami too before and like you say Pichardo there is good and bad parts like everywhere else, but for the cost of living SD wins hands down! Miami is toooooo expensive as a matter of fact the whole US in comparison to the DR is more expensive! I will be there in another few months to find a house, schools, and business opportunities and will be there permanently by Christmas! CAN'T WAIT.