I was also trading off between the two cases. Ended up going with the R4 (see my signature for the gory details) because I didn't have an opportunity to see/mess with the 550D...and the R4 seems to go on sale one week a month at Newegg for $80. I really need to post some photos.
Cable management was a breeze. You don't have 2 inches, but everything fit. Place the mobo power cable first and then everything else can fit. All in all, it was a pleasure to build up a PC in this case. The included case fans are quiet @ 5V, but not silent. I'm guessing the same is true with the 550D.