The lens on the Q is absolutely stunning, as is the build quality.
I played with a fair bit before I ordered one and the user interface works well for me. It is not especially adjustable I think, but I do not expect to need to adjust it.
Basically, if I wanted a 28mm Leica lens for an interchangeable lens camera, it would cost me as much as the whole Q.
My general walk around camera for a couple of years now was a m4/3 GX-1 with a 14mm pancake, so I am used to the 28mm look.
In practical use, the 35mm mode works pretty well. In terms of depth of field, it is roughly equivalent to using a 35mm F/2.8 lens with a 16MP sensor.
At 50mm equivalent mode you get 6MPs and the equivalent DOF is around F/5.6, which is not ideal for portraits. Generall, in 35mm equivalent terms, I like the look of somewhere between F/2.8 and F/4 for portraits if you use a 50mm lens.
Generally, for portraits I prefer somewhat longer focal lengths anyway and I plan to retain some of my m4/3 gear, most notably a 45mm F/1.8 Olympus lens just for such purposes.
As far file saving goes, I routinely shoot in RAW+JPEG mode since I like to preview my images on my phone or tablet, paired to the camera. I need JPEGs for that. I use that to screen and mark images and then develop RAW files only for the ones I like.