If you want a nice easy stay with a great host I cannot recommend this place enough. It is a good size and stylishly decorated and you are left alone if you want to be. The best thing is the breakfast! Lots of nice things lovingly prepared, it really sets you up for the day.
Location-wise its best for the villa borghese, but loads of buses stop nearby so you can get anywhere easily. I took 15 minutes to walk to termini station.
All in all a great place to stay