Just finished the 3rd of 3 stays in 2 weeks. Again received an Imperial Club room, which is in the renovated building (2 floors only) above the executive lounge.
As noted, this location isn't quite as convenient to the Ring as the Marriott, but it doesn't take long to get there, whether by tram, or switching at Wien Mitte or even walking depending where on the Ring one is going.
The hotel is very good about upgrading elites, whether to the club rooms or to jr. suites. After staying at the property 4 times & receiving jr. suites 2 times & club rooms 2 times in the renovated wing, truthfully in the future I'll just request an upgrade to Imperial Club. The rooms are huge, bathrooms are great, etc. Really enjoyed the soaking tub & also the big rainforest shower.
Since I'm just coming back from a long holiday, it will probably take me some time to get photos uploaded of the new rooms but I'll do so & post a link.
Cheers.