So, if I read the news correctly, I can either start receiving my 3 GH/s share from the data centre operations right away (as soon as it's officially operational), or to wait for the Neptune to get developed and have it hosted at the aforementioned data centre? Correct?

Sound like a good option to me. I have a rig hosted with them now, and it's been operational 24/7 since it went on-line. So I am happy with their handling of the hosting. When I bought Neptune, it was at the limit of my power and, not least, cooling abilities at home, so I was actually asking KnC if they would provide hosting for Neptunes. It seems they listened.

Currently, I don't see any downside...