16in rims vs. 20in rims?

[Old65C10]

The Sub I just bought is a 90 2500 4x4 (V2500?) and the PO put some 20in rims on it with 305/55-20 tires. I need to replace the tires, they are getting down and I will have the money now to replace them.
From my research the 20in tires are not that different in price than the 16in that would be the same size (285/75-16). I would need to buy some rims, but I have found some used on CL that would work. I could sell the 20's to someone that wants them.
Is there any advantage, to keeping the 20's, or getting rid of the 20's? At first I really hated them, but now I am not too sure if I hate them or like them.
Here is the picture of it at the dealer.