I honestly cannot recommend this place highly enough!
The location is totally spot on (you'd need train/public transport only if you are going outside town), the apartment is clean, spacious, super cozy and has got eveything you could possibly need!.
Marcello is an absolute g, gave me loads of recommendations and handy little tips the day I arrived as well as during my whole stay - local hidden gems, nice beaches in the Palermo area, transport tips etc. He replied to all me messages very promptly too.
Seriously, I'd be surprised if you find a better place to stay whilist in Palermo!