I have an original Rick Prentice step -- yup Rick, that puppy is a prized possession . I also have one made by a chum of mine in Debert. Rick's is 5/8" steel rod with diamond plate. Dale's is 1/2" rod with diamond plate. Dale's is great and I use it daily - but it does flex a bit. Rick's doesn't flex at all. There is the difference. Now mind you I am a little lighter than I used to be .. normally, but a tad bit heavier than I was after I got Rick's step. 1/2" is suitable for 175 lbs or less, 5/8" is suitable for 175 lbs or more
I also have my own version of a George Willer step. That one is going on Granny I think - my blower unit. Much stronger and better suited to winter operations.