Pros
S&L is a privately held organization with a long history in the power industry. With such history and the level of experience in the sector, one would think that that the firm could offer somewhat a reasonable level of stability and growth that employees look for. If you have the capabilities and drive, you will be promoted approximately every few years at the lower Associate levels, and promotions into higher level positions will take more time.
Cons
Most if not all of the owners of the firm have been at S&L for their entire career (look this up for yourself). This means that if you are looking for this type of career path, you must navigate the landscape and work your way up for the next however many years. There is not really another path. If you are looking for a few years of experience, this could be a place for you; however, be prepared to work with some managers who have no where else to go. This is a reflection on S&L more than the managers, because I do feel that the managers have good intentions. Co-workers in general are great, unless you work with those who are unmarketable and have been stuck in their role for a number of years. They are not happy themselves, and they will not bring you joy. Have a look at other firms in engineering design, and then then make the best decision for yourself.