Pros
This is a family owned business, which can be a benefit. Generally speaking, projects that have visibility of the owners can be fast-tracked and avoid the usual bureaucracy of a public company. Most of the engineering staff are pleasant people, although not the 'cream of the crop' given the low compensation.
Cons
The morale is very poor among most of the engineering staff. Creativity is usually stifled by the oppressive management style. The structure of the engineering department is quite top-heavy. If you are concerned about salary, don't bother with Dart. The M.O. seems to be focused on filling positions with people who are not qualified to go elsewhere, and thus cannot demand competitive salaries. There are individuals who are exceptions to this rule at Dart (talented and not concerned with compensation), and Dart is lucky to have had them on staff for 20-30 years. For most others with any real expertise, tenure seems to be about 2-5 years at best.