zedd- I havent heard too much about that brand but i've seen some around on cgn. honestly so many companies are making ars now but around that price point Olympic seems to be one of the better ones or core15/windham
ill show you a Olympic next time.
crs- the barrel, gas length and rail i believe. both are great it'll come down to preference. unfortunately there's no dd in house atm so not too sure about that going on sale.
come pass by soon im not in weds