Well, I really enjoy my blu-ray drive, and watch blu-rays on it pretty often. I have another one being used for my OC Panel that came with my motherboard. And have a few empty ones left still, that I may add an sd reader for one day, have not decided yet. I don't care for external devices, and don't really care for using the external hard drive I use for saving some of my recordings, and I plan on replacing it with another hard drive for internal use later on.
There's two bays though, on my R4 all I use mine for is just my flash card reader and my BD-R drive - which I use more for backups than I do for watching movies. I will say that watching BD-R movies is more of a pain on the PC than it needs to be, I generally wind up watching the iTunes or Google Play files that are included with the discs.