Pros
Pay is decent; still some great folks working in the trenches; working with open-source is always nice.
Cons
Since getting bought by NantHealth, OpenNMS has been systematically neglected. Nant's executive team was more interested in making OpenNMS grow and look like a "real" company than actually executing a strategy. They ballooned the company by 10x the number of employees, but failed to invest in the right way to move the company forward; instead they tried throwing a bunch of spaghetti at the wall and came away baffled none of it turned into revenue. Now it's 3 years later and we're still in the same place we were when we started: a venerable and useful core product, but nothing to show for the new plans we needed funding for in the first place.