Pros
Imho all good reviews on glassdoor were mostly referring to HQ office in Kansas. Branch offices were quite different depending on your local projects and local management. Mine wasn't good. Often pressured us to meet unreasonable deadlines showing off to HQ. You can't work from home even you live far from office.
Cons
Lack of opportunities unless you are in Kansas. Garmin trying to evolve away from handheld gps device which has been its expertise for decades. Problem is years of inhouse driven development and lack of industry awareness in new approaches and new technoligies. Culture is very conservative and very "inside" the box thinking. New engineers leaving after about 2 to 3 yrs once they realize it takes an arm and leg to put this company on the right track. Scheduling is awful cuz garmin had been in its own domain for so long and lack of expertise in collaberating with other vendors. However it is good for intern and less experience engineers. After all they do have 20+ years of legacy code for you to learn.