The solution is very scalable. If you set up a very large database, billions of records, or so, if you have enough memory, enough disk space, it's quite easy to do. I haven't set it up in a cluster environment, myself. I have other clusters, but they are sort-of Malware normal. OLAP and LTP volumes perform quite well. 

Right now, we have 30-40 users. We'll most likely add more users using RBI and KIP View, but for now, our user population is stable at around 30 or 40. 

I don't have any experience with the scalability, but I would say that it is scalable.

We have 20 to 30 people using this solution.

Not really applicable. But we have a team of 6 developers here and we use the source control successfully.