We have Panasonic splits, Daikin splits and Panasonic window types. All inverters.

Panasonic window types are a lot quieter than non inverter window types but there is a tiny bit of noise from the louver rattling a bit when set to oscillate. Maybe some lube will do the trick but I don't like the idea that we will be smelling the stuff the whole time while sleeping.

Panasonic window type also does away with some features like Econavi and Nanoe G found in their split units. And the fan only has 2 settings, low and high compared to the splits which offer multiple fan speed adjustment.

The Daikin splits are the quietest and are cheaper if you know where to buy. They also claim to be the most energy efficient and environmentally friendly through the use of R32 refrigerant vs Panasonic's R410a.

For me if you can go split, Daikin is the way to go.