Pros
I spent less than 5 years at SEL and I enjoyed my time there. "Most" people (I'll talk about the rest in the cons section) are very friendly and they have a great work environment. I was a Field Application Engineer and get the freedom to choose your own work, what relay do you like to support the most, how many app guides to write vs teaching, etc. They buy you Friday lunch, which might not be a big deal, but at least you're getting "free" food on Friday. You also have the opportunity to write papers and get exposed to the power industry at conferences.
Cons
This company is 100% employee-owned, but that does not matter, Ed still does whatever he wants and if you even consider speaking against his ideas then you get immediately fired. The salary could be better (it's slightly below industry average) and the bonus is a joke (My last year's bonus was roughly $1,100 minus taxes), and Ed's excuse for not giving a good bonus is because he spends all the money in making new buildings and buying jets. There is no real growth path, and you pretty much have to be one of the "chosen" ones to move up in the company. I mentioned that most people are friendly, but some higher-ups are rude and you really can't complain to HR, as HR is owned by Ed and his friends, if you don't mind dealing with these people, or sucking up to them, then don't count this as a con. Finally, if you ever want to move to a different position then you might have to relocate to Pullman, which is in the middle of nowhere and flying there takes a whole day. Finally, there is so much work to be done because they don't hire enough people, so keep that in mind, you'll be working weekends, staying late, and all that overtime is uncompensated.