Stopping there from Cuzco, the difference was night and day. The depressive fog that blankets the city seems to set the mood for the majority of the populace. Originally planned to stay there 3 nights, I'm glad we cut it short to 1 night since we visited several ruins in and around Cuzco after Machu Picchu. The people are nowhere near as friendly or hospitable, there is basically no culture left and the visible divide in social classes is disgusting.
Insider Tip:Unless you have planned to visit specific sites in Lima, I would advise you to stay there 1 night. Not going to miss anything you haven't seen in any other major city. Spend your time elswhere like Cuzco!