Since power retractable running boards are one of my favorite features, I would never replace them with fixed boards. I would only replace with the same ones I have.
Penetro 90 is always worth a try and usually fixes the running board issue.
My friend's boards were almost dead, made a lot of noise and hardly ever worked. We cleaned them really good, by spraying Totally Awesome straight concentrate all over them, then high pressure cleaned, let dry, saturated them with Penetro 90 and kept opening and shutting doors until they got good penetration, greased them up and they work like new. Most of the time the bearings are not bad, unless it is a much older vehicle, never cleaned or constantly used in mud, salt, etc. conditions. I've been fortunate as I take my Expedition to a car wash that does under carriage as well. So, my boards and hinges are very clean. I also clean and grease the hinges every couple of months.