The fact that a window air conditioner uses a compressor that is situated outside the room should in theory make them quieter.
Portable air conditioner vs window air conditioner.
For the most part when it comes to portable ac vs window ac the window units win.
Portable air conditioners are usually around 100 more expensive than window air conditioners of the same cooling capacity.
Portable ac units hover around 70 db while window ac units tend to be near 50 db which is one eighth quieter.
Air conditioners are usually quite noisy though you can find quiet air conditioners.
Window air conditioners and two hose portables are much better.
Also because portable air conditioners are generally larger and start at a higher btu h they will be more expensive than window units with a lower btu h.