From the friends who live in BA, I can verify that if you live in the area that the marine police cover, you're in very good shape. I've stayed at the Sheraton once, and wasn't impressed. I've had pretty good experiences at the Hilton. I don't find the lounge staff to the the caliber of my favorite SA Hilton, in Sao Paolo, but they're decent.
I have rented a couple of apartments in the microcentro area, and it's a decent area, but you obviously need to keep your eyes open. I just wish I could get a good apartment for $350 a month, like I used to.
I don't recall hearing about the Conrad before. That should be interesting!