It depends on how you define success. Rebel that I am I have been experimenting with a Dual Lite. I first used an old USB 2 jump drive without success. I then hooked up my least-likely-to-succeed laptop drive, a Utania (what?) from Cloverhitech (who?) for a few days and it worked. For a few weeks, now, I have been trying a 128 GB Samsung USB 3 flash drive without problem. Of course, I don’t know if I have ever viewed more than one stream while the Tablo was recording and it only has two tuners but so far, so good. Also, I have live and recorded bit rates set to 720 3 Mbps that keeps down reading and writing (I hope). Time will tell.
I really don’t like the extra cabling and clutter of an external drive and, thanks to Tablo Ripper I can backup any recordings that I would hate to lose should the flash drive fail. If it does, I will switch to an HD.