Pros
I am a current engineering intern at Koehler (since February 2017) and it has been an amazing experience so far. Every employee is extremely nice and will always, to their best ability, try to help with any inquiries. Management and HR are super flexible and will work with your schedule to accommodate your personal needs (I am a student as well). They do challenge you with difficult tasks. However, this makes the internship more valuable in terms of learning how the industry works. I can now say I have extensive knowledge on petroleum testing as well as a fundamental understanding of real world instrumentation design from this internship alone.
Cons
Again, the work can be a bit difficult at times but rightfully so.