As a foreigner who's been living it, I'll tell you the Naco, Piantini, Bella Vista areas are great for business but like Manhattan they're mostly apartments built vertically, not much parking, not much green area, crazy traffic, lot's of very rich, lot's of very poor. Great for a single couple, or couple with kids who've left the nest, maybe one kid. Me, I prefer a yard and a full house not an apartment, but it's an opinion that not everyone will share.
Gazcue, where I'm staying (Green House Aparta-Hotel, I recommend it) is what I would call the Zona Colonial. It's ok, but there's a lot of foreigner night life if you know what I mean after dark + the houses tend to be older, the streets samller. The rents (not the asking prices) tend to be more reasonable than Naco/Piantini/Belle Vista but again the places are older.
I've seen he Zona Oriental (as best I can figure out it's a nice way of saying "The other side of the bridge where the poor people live") as it seems to be massively under construction. It may well be a great neighborhood in a couple years but it appears right now you're living in an area that is underdeveloped and not quite as safe as the West side of the bridge. It's not bad, just think of whatever neighborhood in your area that's not finished and that's the Zona Oriental.
Now, since I have kids I'm kind of a suburb guy as you tend to get more house + yard + schools + shopping malls for the buck. I have yet to check out (but am going to look at this week, after months of being told to) Arroyo Hondo I-II-III-Altos and Evarista Morales. I think FOR US these are probably the best places (i.e. the suburbs), with the best schools (many, bilingual ((no brainer here)) geared towards the bilingual student).
We're also thinking very hard about moving to Santiago as the price/M2 seems to get you more bang for the buck.
Hope this helps..............
I realize this budget does not work for everyone, just passing along some recent first hand info from a guy who knows a little bit.