Installation: one click if you have the right hardware
On Windows with an NVIDIA GPU, you download a zip, run `webui-user.bat`, and it installs Python, CUDA, PyTorch, and downloads a base model automatically. First launch takes 15 minutes while it downloads 5GB of dependencies. On Linux it is `git clone` then `./webui.sh`. If you have an AMD GPU or run on CPU, the installation is more painful. The community wiki has guides for every hardware config, but expect 1-2 hours of troubleshooting on non-NVIDIA setups.
The extension ecosystem is the real value
AUTOMATIC1111 has 200+ extensions in its built-in extension browser. ControlNet (pose, depth, canny edge guidance) is a one-click install. ADetailer fixes faces automatically. Dynamic Prompts lets you generate hundreds of variations with wildcards. The img2img tab lets you upload a photo and regenerate it in any style. I used the batch img2img feature to process 50 saas.pet screenshots into stylized review header images. The entire batch took 8 minutes on my GPU.
What AUTOMATIC1111 does that Midjourney cannot
Inpainting: select a region of an image and regenerate just that part. I generated a landscape, then inpainted a character into the foreground. Midjourney cannot do this at all. img2img with denoising: upload a wireframe sketch at denoising 0.6 to get a polished illustration that follows your composition. Upscaling: 4x upscalers like ESRGAN and RealESRGAN that turn 512px images into 2048px. Training: you can fine-tune LoRA models on your own dataset within the WebUI. Midjourney is a black box. AUTOMATIC1111 gives you the controls.
Performance: what hardware you actually need
Minimum: 4GB VRAM (GTX 1650 works with --medvram flag, generates 512x512 in 30 seconds). Recommended: 8GB VRAM (RTX 3070, generates 512x512 in 3 seconds, 1024x1024 in 10 seconds). Best: 12GB+ VRAM (RTX 3090/4090, generates SDXL 1024x1024 in 5 seconds, supports ControlNet + upscaling simultaneously). CPU-only: works but takes 5-10 minutes per image. Mac M1/M2: works via MPS backend, 2-3x slower than equivalent NVIDIA GPU.
Why I switched to ComfyUI for production, but still use AUTOMATIC1111 for learning
AUTOMATIC1111 is perfect for learning because every parameter has a visible slider. You change the CFG scale from 7 to 10 and immediately see the difference. You learn what samplers do because the names are right there (Euler A, DPM++ 2M, DDIM). For production batch work, I switched to ComfyUI because the node graph lets me build pipelines that AUTOMATIC1111 cannot: chaining 3 ControlNets, running a face restoration pass, then upscaling, all in one click. AUTOMATIC1111 is the best learning tool. ComfyUI is the best production tool. Use both.