for me, looking elsewhere had nothing to do with price, but rather just the fact that SO only offers like 6 different items. So I went searching......
Check out "wall control". I just ordered a few things to try out and found this: their stuff fits the slots, BUT anything with multiple slot engagement will require some mods to use. SO sets their slots on a 3" spacing. Wall Control uses 2", so you can use singles, no problem and 6" or 12" wide stuff like shelves, but a lot of the Wall Control stuff is odd - 8" or 14".
I just got this can holder:
https://wallcontrol.com/Catalog/Hooks/HooksCatPG11.htm#asmch014
I liked the idea of hanging more stuff to the outside of the rack, so I wanted to try it first. when I got it, I found out about the slot spacing issue. To make it work, I split the mounting brackets and welded in a piece to stretch 'em out to 15" to match SO's arangement.
The finish is supposed to be powder coated, but it's pretty chintzy compared to SO's finish.
Edit: I can also tell you I have bought some generic pegboard stuff from Lowes and found a lot of it does actually fit the round holes. Stuff like a hanging bin thingys that has 4 pegs ended up being the right spacing for those holes. The stuff was all "store brand" (Blue Hawk, I think) and the single little hooks and such work fine, too.