I have stuck with 1.5 because SDXL wasn't that exciting to me and ultimately I haven't been clear what software needs to change (and how/why) to be "compatible"
Its extremely similar, but not drop-in compatible, no.
Whats more, small changes make it compatible, but larger changes are needed for SDXL to work well.
Personally I find SDXL to be a huge upgrade, at the cost of performance, hence I am using Fooocus but keeping an eye on https://github.com/FizzleDorf/ComfyUI-AIT
As I have been preaching on HN, just don't use A1111 for SDXL.
And yeah, the difference is dramatic!
Why, what am I missing by doing so?
Less jankiness.
For me, personally, better hackability, especially in `diffusers` UIs (though Comfy-based UIs seem to be SOTA for SDXL).
EDIT: Also, other user interfaces are more "suited" to SDXL and its presets+style prompting. A1111 is very much built for SD 1.5
I just had to update A1111, download the sdxl model, download the sdxl refiner model and set the refiner in the refiner dropdown. That's it. So compared to other models it is just one additional dropdown click.
You won't be able to use the LoRAs, etc. you are used to, but you can download new ones that are compatible with SDXL.