I have seen many discussions on this board and many others about Roku's (and other video players) inability to read ExFat drives, but I have not seen anyone request that feature be added to the Ultra. I also have been reading that many people seem to have trouble reading HFS format on the Ultra. Perhaps I am incorrect, but isn't the only reason that people purchase the Ultra is to get the USB access?
So this is my official request, ROKU, please add ExFat access to the Ultra.
Another option would be to add access to an ExFat app the way Synology does it. Yes, it costs $3 but solves ALL the incompatibility issues.

Microsoft has several patents on ExFAT, so it would cost money. That is why Synology charges for it. Most likely, only a tiny percentage of users use USB with their Roku's. Adding ExFAT support would not be a simple add-on, but a separate firmware.

The HFS format of a media file has nothing to do with the way the drive is formatted. HFS is usually in either an MP4 or MOV container, both of which the Roku will play from any supported device. I believe you are making a valid request, as many people use exFat drive formatting. But I wouldn't say the primary reason for buying an Ultra is the USB port. I believe the Ethernet port is the primary reason, and with the Ultra 4640 the optical out was another reason. Other than testing it once, I've never used the USB port on any of my Roku players. But then I keep my media on a server so any device on the network can access them. Plus that way I don't have to worry about file compatibility, as my server will transcode any unsupported codec or container.