not really
I'm using both and there's films/shows that Showbox has that HD cinema doesn't
and vice versa
(for example, The Raid 2 is on showbox but is nowhere to be found on HD Cinema, While Enter the Dragon is on HD cinema but nowhere to be found on showbox)
it's best to have both though, it's good to have a 2nd, 3rd or 4th option in case one app acts up or doesn't have what you're looking for.
BTW, for those of u who don't own a stand alone wifi enabled bluray player or a smart tv
(or if allcast doesn't detect ur smart tv), u can stream showbox/hd cinema directly to your xbox360
(I have not checked to see if it works on PS4/XB1, I checked PS3 and it didn't work but it definitely works on xbox 360s ) as long as they're connected to the same wifi network