Two things I learned not to skimp on early in my railroad career: Footwear and rain gear.
I have really come to appreciate Red Wing 2292 logger boots (very supportive, warm, waterproof and long lasting but heavy) and more recently Timberland PRO Helix boots (lighter weight and more comfortable while being adequately supportive, warm and water resistant). Timberlands seem to have a reputation for being very comfortable.
But really, the issue is too subjective for a single solution. It depends on what you are doing, where you are doing it and whole lot of personal preference. I would want a different boot for walking around on a concrete or steel floor in a manufacturing environment than I would for working on course aggregates along railroad tracks. And I have a different pair of safety boots to wear in a business casual office/conference room type of environment where I may need to occasionally step out into the field.
Someplace like Whistle Workwear will let you buy a pair that you initially like, wear them around the house for a week or so and return them if you aren't satisfied with how they are feeling.