mainly cooling options. the corsair case is a good case, but limited on options
in cooling. if you are a set and forget kinda person, no need in updating. but
if you are a gamer, enthusiast, or look for the nth in cooling the R4/Midi
are a better choice case.
many have tried to custom loop the 550D and its just not fesible to run the
tight rads and limit the hardware due to the shortness of cooling. as the R4/Midi
are rich in cooling options and still stay a quiet case for no one to hear.