I stayed two times in Lex Luthor's, my first nigths ever in south America and a month later. I loved it both times! Luis, the lovely owner that makes you feel at home immediately, prepared us some really nice Pisco sour and arranged a descent discount at his brothers hostel in Arequipa, Yunta Wasi, also very nice.
If you are looking for a cosy, family like hostel, in Miraflores, but also with enough young people to go out with, go to Lex Luthor's!!

This hostel is in a great spot in Miraflores. It is small, the staff is very friendly, and we got great sleep here. The bathroom wasn't as clean as we would have liked, but the bedroom was comfortable. We arranged an airport pickup through Lex Luthor and he was waiting for the airport for us like the promised, even an hour and a half after our plane was supposed to land. We would have liked somewhere outside to sit and relax, but the price is reasonable for what you get.

Good breakfast, good tourism info, good beds. Not so good showers (electric) but had a public bath with good hot water from a thermo.
Good location, near the sea, but a lot of stairs to reach it (Lima has gullies).
Lex and mrs. Lex, excellent people!