I've recently upgraded wheels to Shimano R500, from Cerchi Nisi T Due. Before;
After;
They provided me a total weight loss off nearly 500 grams. Also they have obvious smoothness advantage over the old ones. Got the rims for 60$ as used.
Compared to used wheels market, they can be count as free.
I will never use any wheel, that is under the entry class (entry such as Shimano R500). They are useless, really.