>Midjourney is more popular (from what I'm seeing) than Stable Diffusion at the moment because it's better at the moment. Midjourney is closed-source.

Midjourney is easier, its not better. The low barrier to entry has it popular, but it isnt as realistic, doesnt follow the prompt as well, and has almost no customization.

SD is the holy grail of AI art, if you can afford a computer or server to run SD + have the ability to figure out how to install python, clone Automatic1111 from git, and run the installer, its the best. Those 3 steps are too much for most people, so they default to something more like an app. Maybe it is too soon, but it seems SD has already won. MJ is like using MS paint, where SD is like photoshop.

I just want to add my $0.02 currently working at a games studio that is integrating AI generated art into our art pipelines.

Midjourney definitely generates really high quality art based on simple prompts, but the inability to really customize the output basically kills its utility.

We heavily use Stable Diffusion with specific models and ControlNet to get customizable and consistent results. Our artists also need to extensively tweak and post-process the output, and re-run it again in Stable Diffusion.

This entire workflow is definitely beyond a Discord-based interface to say the least.