I too am biased toward Peru, having lived there for several years. It's a wonderful country with a lot to see. An earlier post mentioned "low crime". I suppose you can ask, relative to where? but anyway in Peru there is a lot more "snatch & grab" type crime than most places in NA where I assume the OP is from. You have to be careful at all times and in Lima for example you need to take care where you venture out, especially after dark, as robberies in the street are common, and the "good" parts of the city are often very close to the "bad" parts, and sometimes it's difficult to distinguish between the two.

That said, I think Lima is on par with places like BA, and probably overall safer than Rio, Caracas, Quito/Guayaquil, etc.

If you're interested in seeing archeological and historical sites, and experiencing a cuisine that is unique in the world and one of the best, then Peru is the place to go. If you're interested in a rain forest adventure, you can do that in Peru too but you'll find it easier in a place like Costa Rica.