As mentioned earlier, Seagate added the popular Plex Media Server to its other supported apps shown below.
Seagate Personal Cloud apps w/ Plex
Plex is supported on Windows, MacOS, Linux, FreeBSD and many NASes. The screenshot below is the Plex home page from the 2-Bay, running on port 32400. I'm not a Plex expert, but it looks like everything is there, including the ability to play video in the browser window.
Plex Home on Seagate Personal Cloud
Support on all NASes, however, is not equal. All the listed NASes will run Plex and support its basic DLNA and library functions (except for old Sparc-based NETGEARs). But video transcoding is not supported on PowerPC or ARM-based NASes, only Intel. This Google Docs spreadsheet compiled by Plex community members is a great resource if you're wondering if the NAS you're considering will support transcoding.
I tried paying an old video from a Canon digital camera that usually causes media players to throw fits (480p @ 30fps MJPEG, mono PCM audio) and wasn't disappointed. Sure enough, the in-browser window properly informed me that my viewing was not to be. On the other hand, trying to play the same file using a Roku Streaming Stick running Roku's Plex app, didn't throw a similar message.
Trying to play MJPEG video
Instead, Plex dutifully launched its transcoder and maxed the CPU, trying to play the file, while the Roku app just hung.
Trying to play MJPEG video - Personal Cloud monitor
My luck was different trying to play a Blu-ray rip of Star Wars Episode 4 (MPEG4, 1920x816, 24fps, DTS audio). This time, the in-browser player didn't throw the warning, even though the Plex New Transcoder was running. The CPU was again maxed, but the video played, albeit with enough pauses to make it unwatchable. The Roku Plex app also was able to get the video started after a long "loading" cycle. But with even more pauses and lower resolution, the video was again unwatchable.
I tried a few other experiments and also checked the same files running plex on a QNAP TS-251 (2.41 GHz Intel Celeron J1800 Bay Trail D dual-core). It was able to play them all, with the Plex Transcoder using about 63% of the CPU. The moral here is that your success with using Plex in general—not just on the Personal Cloud—will depend on the source material, the capabilities of the player and the connection between them. On the Personal Cloud in particular, however, if your video file needs to be transcoded, you'll be out of luck.
The Personal Cloud was tested with 18.104.22.168 firmware using our Revision 5 NAS test process. Tests were run with the two 4 TB drives in single RAID 0 and 1 volumes. Comparing the Benchmark summaries for the 2-Bay and single-bay Personal Clouds shows many improvements in the 2-Bay. RAID 0 File Copy Read performance almost doubles and write increases over 50%, too. NASPT File Copy From NAS (read) improves just shy of 300% from 36 to 104 MB/s.
Since I didn't lay eyes on the single-bay's processor, I've reached out to Seagate to confirm that it's the same for both products. The other possible contributors to the differences are newer firmware on the 2-Bay and RAID 0 vs. single drive.
The NAS Ranker ranked the 2-Bay #8 out of nine two-bay NASes tested with the current test process. ASUSTOR's Intel Atom CE5310-based AS-202TE ranked right above it, Seagate's NAS 2-Bay, which also uses the same 1.2 GHz Marvell Armada 370, ranked right below. The currently top-ranked ASUSTOR AS5102T rings up at $408, sans drives and with two 4 TB Seagate NAS or WD Reds adding $320, that's not a fair price comparison.
Instead, I compared the #9 Seagate NAS 2-Bay with the Personal Cloud 2-Bay. The NAS 2-Bay is actually a bit more expensive at $500 from most vendors than the Personal Cloud 2-Bay. Aside from the fact the NAS family supports iSCSI and the Personal Clouds don't, the two families' feature sets are pretty much the same. The NAS 2-Bay beats the Personal Cloud 2-Bay only in the total Mixed Read/Write Benchmarks, and then, not by much.
NAS Ranker Performance Summary Comparison
Seagate looks like it has done its pricing homework on the Personal Cloud 2-Bay. At around $450 for 8 TB RAID 0 or 4 TB of RAID 1 storage, it has a combination of price, performance and features that's hard to beat. Like its single-bay sibling, the Personal Cloud 2-Bay should be very attractive to the home user who wants centralized storage with simple setup, wide selection of backup options, flexible media serving and the ability to easily grab files when away from home.