Pros
I've worked at Spire for 2 years now and this is definitely my favorite job I've had. I had worked for nothing but big corporations before starting at Spire. The contrast between working for a big corporation and Spire is night and day. Pros of the company are that you get a small company atmosphere where everyone is a team. Everyone works toward a common purpose of helping the company grow. At Spire, I feel like my work actually has purpose and directly impacts the business. This has made me work even harder and care about my job more than any I ever had. Expectations are high, but also attainable. If you work hard, you're rewarded. I've had several salary increases and a promotion since starting all because I put in the hard work.
Cons
The biggest con I can think of isn't really even a con, more of a side effect of the company. This is a growing, but still small business. There aren't always a set of way of doing things, and in a lot of cases with new hires, people are hired specifically to help standardize the way things are done. People wanting to work for Spire should have the mindset that since this is a small company, you will be creating the standard.