Pros
I personally loved my time at Opsview. Because of the nature of the product, you're introduced to such a wide variety of different technologies ranging from Linux to Windows, cloud to on-prem, networking to offline systems, and how different types of customers utilize certain aspects of all of these technologies. If you put in the time to learn and fully grasp the technologies covered here, your career projection is limitless.
The team itself is comparatively small (especially the US office), but I viewed that as a good thing, as you're able to make a higher impact. Additionally, it allows you to wear a few different hats if you'd like to try different projects and responsibilities.
The team members were my favorite part. Opsview does a great job of not only hiring the right people for the right job, but also making sure that they're right for the team; I made lifelong friendships here.
Cons
Considering the office location for the US, the pay was not competitive in comparison to the opportunities and cost of living in the surrounding towns. HOWEVER, I know that this was being corrected after my departure, so this may be better now.
The US office team is extremely small, and depending on your role, it can be hard to take personal time off; not to mention, the remaining staff wasn't setup for success when someone was off. For example, if just one US support person was off, there would only be one support tech from about 1pm-6pm (after the UK office goes home) that would have to cater to all calls, web conferences, and support tickets coming in.