Honestly I have nothing but good things to say about Steam Workshop. Implementation is very easy and the look of it can be very aesthetically pleasing if your community has an easy way to make good thumbnails! I would say my biggest gripe with it is that it can't be accessed without Steamworks, so I think it is a smart move that you've already got ways built to share content outside of Workshop. It's an amazingly convenient system that adds a lot of longevity to any game, so I still recommend implementing it if you can, or at least commit to implementing it and let your Steam forums know it's on the way.
Keep in mind that trading cards and some other community features are locked out until you reach a certain sales threshold on Steam, so get those Wishlists in!
Little known fact: Mondrian's levels were originally ini-based, but the load times were atrocious. About halfway through early access we switched to array files which are loaded into RAM, then generated, and then flushed from RAM, all in under 2 seconds generally. We actually had to artificially inflate the load times because Steam Decks would trip over level starts from the fast load times. But thanks to the change, we have a maximum limit of about 15,000 blocks, rather than the 99 we had with the INI files, at the cost of about 25kb of extra space.