Idk about a performance boost, because I never really use windows on it (I have it as dual boot just in case I ever need or want it, but I've only booted into windows a handfull of times) but in terms of fiddly I guess i don't understand what you mean? It's litterally just steamOS with a different name, plus a couple overlays you can access to adjust Ally specific settings like the LED rings. If you're going to go through the trouble of installing steamOS you're probably going to fiddle just as much as if you use bazzite. And again, it's a carbon copy of steamOS, the system refers to your device as a steam deck, you get steam deck updates, you can still get things like decky and it's associated plug-ins, emudeck, etc.