We stayed at Wonder's place for a week, it was good overall, near Taksim square and around 6 minutes walk to the metro station.
The place is nice and clean, heating was good, well equipped kitchen, comfortable beds, very fast internet and a BIG TV.
The host was friendly and allowed us to check in early which was very nice of them.
Only negatives are some noise a couple nights from outside the nearby bar, a bit tough stairs especially for old people but should be no problem if you're young. Apartment also needed some final touches, especially the restroom, and the host was not able to provide a baby crib as he promised, since he found it broken or something, but thankfully there were enough beds so we used one for the baby.