Well, it's really a matter of personal preference and it boils down to whether you need the F2.8 or 50-105mm focal range.
I used to own 17-50, 16105, 18250 and 1680cz. All I can say that I kept the tamron the longest while the other 3 get sold quite quickly. Probably due to the fact that I am shooting low light without flash indoors most of the time, so 50mm is enough for me and F2.8 is very versatile.
I remembered I went for holiday and I only used 1750 as my walkabout lens, whether indoor or outdoors, it's very useful and I didn't need to change lenses as I actually do not have the time to do so.
In terms of sharpness, I can say 1750 and 1680cz is quite a good match. For the same aperture and focal length, they are quite similar, where Tamron has the advantage of bigger aperture size when needed.
16105 and 18250 are quite similar as well in terms of IQ, and if you compare the focal length of 18-105mm, the 18250 actually is a "faster" lens as it doesn't stop down as quickly as the 16105. Example is that 16105 is already F4 once you zoom pass 17mm, so it's really difficult to use if you are indoors, unless you use flash.
I would say, get the 1750 as your indoor and 18250 as outdoor, these 2 combos are quite formidable, especially paired them both with the excellent 35/1.8 which makes them my trinity lenses.