Pros
Pays really well and offers reasonable PTO with some profit sharing options and/or bonuses. You're rewarded for being detail-oriented and self-motivated. No one is going to micromanage you here. A lot of support is offered during the training process.
The office environment is pretty casual and everyone is generally very friendly. There's no pressure to work long hours or on weekends. You can leave your work at work.
It's a tedious job, but it needs to be done. So you'll get some job security from that.
Cons
Absolutely zero opportunities for career growth. The skills you learn are not transferrable and you will have a hard time selling yourself in the job market after you leave. The company isn't interested in innovation or growth for itself, let alone employees, and feedback along these lines will often go nowhere.
Because there's no opportunity to grow, advance or shift roles, you'll eventually get bored.
The company is frustratingly comfortable with outdated technologies.
The owner can ask overly personal questions and be very reactionary.
There is a sense that people don't feel comfortable sharing professional or academic accomplishments earned outside of work. I'm aware of more than one employee that made efforts to hide that they earned a post graduate degree part time while working for Check Fund Manager because they were concerned about how the owner would react to it.