Pros
Endless opportunities for career advancement, training, and personal development. A lot of long time employees have "started at the bottom" working as an intern, assembly line worker, or technician and over the years worked their way up to high level engineering positions. Cummins provides the opportunities to make this possible by being flexible with changing jobs and providing endless opportunities for training.
Cons
In some areas there seems to be a culture that you must work as much as possible, even to the point of skipping off-site group events to make your boss happy and look better than your co-workers during evaluations. This same culture seems to bleed into taking vacation time as well as people are too worried to fall behind and look bad.