Pros:
Boutique modern style apartment so close to historic center!
it was a great pleasure to stay there.
Stefan provide full detailed information how to get into apartment, you will not need to meet anyone in order to check in, it is a great plus for me - as we arrived very hungry , we just dropped our bags and went for the dinner - no time lose!

The apartment has double windows - no noise from outside (very important for us).

Basic modern kitchen all what you need to prepare meals, also there is a coffee machine!

There is enough space for two persons.

Street with tons of shops, bakeries, restaurants and etc, very close to metro.

Cons:

No A/C but fan , in October i don't need A/C but in hot summer A/C may be critical.

Bathroom door is just a tinted glass and not sealed - from bedroom you will hear everything what is going on in toilet ... not good experience ;)

Apartment not on direct metro line from WienMitte train station - trains from Airport, you will need to transfer from U4 to U2

I would recommend this apartment. Overall impression is very good!