Great simple solution for a stay in Milan. Great central location. The amenities in the space are quite austere but you don't stay much in your room while traveling anyway.
If you are traveling far I recommend paying the extra fee to have them meet you a the location instead of going to their office to pick up the keys. The process of checking in and giving copies of your passport was not my favorite experience (sending digitally instead of inspecting them in person isn't the safest processing of your personal information) Not to mention you need to send your room mates information too and if you are just friends that is a lot of personal information to share.