I had D90 for many years and sold it for D7100, However the D7100 body looks like its made lightly or cheaper than of D90, is it so? The feel of D90 was solid and hard plastic but with D7100 it seems the plastic of body and even the charger was made cheap. Is that true? I am thinking of being ripped.
According to Nikon's web site, there's some metal under that plastic.
Although I wasn't able to find anything as convincing regarding the D90's construction, I found a number of references to "all plastic" construction, despite its weight.
I believe in this case, you can look at the light weight of the D7100 as a bonus rather than a detriment.