My current startup and my last one, both smaller orgs. I setup both build systems, and initially used SBT in the previous one. In both cases I think it helps that we had engineers from larger companies familiar with a working monorepo; if you've seen one done well you have some aspiration as to what to shoot for with pants, even if it's more than what's currently available.

I'd use SBT again for a locally contained, single project setup. Once you learn the arcana, it works well, has a ton of plugins, and the repl is nice. I don't think it scales well with new engineers or number of projects though.