When I owned my first one, over twenty years ago now, I never saw more than one other on the road. Since then I think that I've seen two (actually in use). There used to be an advertising blurb "Seeing one is rare, owning one is rarer" - seems to have been the most truthful advertising ever.
Looks are subjective. I would never call it pretty, not even handsome but I do like it even though it's difficult to say why.
Values will climb faster than any other K-Brick if for no other reason than rarity.
Mine will get regular use, mileage is less important than cosmetic condition IMO as putting a tatty one right is more expensive than sorting it mechanically.
Apart from the main, upper fairing, the rest are made from very thin plastics (apparently to keep the weight down a bit). If over tightened, the fairing screws can cause the plastic to fracture easily. This led to them being known in some markets as "yoghurt pots":
Most of the plastics are still available new but no longer in anything other than primer. Likewise, most of the graphics are available. There's a lot of plastic to re-paint if it needs it.
Of the colour schemes, many people didn't like the blue/yellow & red/yellow when they were a current model and BMW responded by bringing out the more muted blue/silver, black/silver and black without graphics (I'm not sure what category the Dakar Yellow one falls into though).
Now, however, the original schemes seem to be more sought-after. It looks as though people now understand that unusual styling demands unusual colour schemes.
There's a more pragmatic reason for choosing the original colour schemes as a prospective owner; the yellow transmission is far easier to keep looking good (as long as it isn't chipped):
Whereas the bare aluminium version soon becomes tarnished and requires a lot of graft to clean up:
It can be sorted though:
Rear wheels seem to suffer most, mainly from owners or tyre-fitters who try to squeeze the wheel past the final drive without dismantling the necessary bits to clear the ABS ring:
Finding a touch-up is nigh-on impossible but a little, imagination, time and enamel model paints can approximate the colour:
It will do until I can find a rough second-hand wheel and then see if I can find a powder-coat company who can match the original.
The K1 will never reach the values of some "classic" bikes but I think that before long it will reward the effort to find and keep a good one.