We absolutely loved the Blue Hostel and will 100% stay there again. The only people who should not stay here are people who can't do stairs - there are several flights of stairs. We had no problem with this - in fact, our cardio health increased and they got easier to do over the week lol - but if you can't do stairs its the wrong place for you.
If NOT, it was a fantastic place, easy to get to Termini but not right on top of Termini, a quick shot to the Forum and center city - really everything was walkable and the few places that were not easily walkable were accessible by Metro and other trains - easy to do day trips out of town etc. Maria Maggiore down the street which is first rate. Clean, nice kitchen, great communication with hosts Alessandro and Ercole. A+.