Data Centers in Vienna
Vienna has a relatively small data center density compared to other cities, but there are still a few options worth exploring:
DanubeDC, Floridsdorf: very competent looking, fast interaction possible. They build a second DC on the south side of the Danube, too, probably with high-density cooling zones.
IBM ODC21, Floridsdorf: Bureaucracy; fast; very competent looking. Can do high-density cooling zones.
InterXion, Floridsdorf: "the datacenter". VIX2 is hosted here. A bureaucracy. Can do large-scale projects, as well as high-density cooling zones.
Invitel, Voesendorf: Can do large-scale projects, unfortunately not directly located in Vienna.
Nessus, Favoriten: probably very flexible, small company.
SIL, Heiligenstadt: okay. Sometimes a pita, but things get better.
UPC, Favoriten: probably okay. Flexible pricing.
There are rumors that Verizon and Telia also operate data centers in Vienna, but I couldn't get pricing/info from them.
Most data centers offer reasonable pricing while not being capable of doing proper pre-sales. You better know exactly what you want ahead of calling/visiting anyone.