IMO, difference between 100mm and 105mm is irrelevant, it's more about a tradition within within lens makers (Most brands take 100mm, Nikon for some reason decided for 105mm, most likely to set themselves apart).
However, 28 and 24 mm are slightly different lenses. I am so used to the 24mm that feels more "natural" than the 28mm (that's highly personnal and subjective). The difference in angle of view is not so big, so if you have room behind you, moving a couple of feet back will allow you to put as much in the frame with the 28mm.
But in the good old times of film, 28mm was a more common focal, the saying was that the 28mm is the widest angle you can use without showing excessive perspective distortion, typical of very wide angles. Fact is that the 28mm is a wide angle that gives a very natural perspective, without that "super-wide angle" look.