The solution is scalable.

This solution is not very scalable. As the number of messages increase, you can expect some UAs. Also, if you use excessive conversion among different formats like EDI, you should expect some issues.

We have 60 BizTalk Server users in our organization.

BizTalk Server's scalability features made it easy for us to handle increased volumes of verifications. I rate its scalability a six out of ten. My company has ten users who use it once a week. 

BizTalk Server has scalability issues. The minimum data transfer time cannot go down from hundreds of milliseconds, which creates problems. It is due to the architecture. A group of three to four developers use the system directly daily. There are thousands of indirect users. 

Essentially, you can do whatever you like with these systems, and you do not have to worry about the scaling because if one server is overloaded, it just forwards the message to the next server, even if it were designated to a specific server. It weeds out the messages according to the load. If you want to scale it, you just add new servers. I would say it's easily scalable.

We did not encounter any issues with scalability.

We have not encountered any scalability issues.