The Model 3 manual lists the following two devices as having "[met] the requirements for Dashcam and Sentry Mode use:"
I'm using the Ultra Fit at the moment and it seems fine so far.
Edit: I have the 128GB version of the Ultra Fit and after 2 days I am getting the "too slow" warning every time I get in the car. On my PC i can get a sustained write of ~20MB/s so I'm not sure what the problem is. Going to try a SanDisk SDCZ880-256G-G46 Extreme PRO 256GB USB 3.1 Solid State Flash Drive instead. This is all temporary for me anyway as I am working on my own flavor of the TeslaUSB project to try and get boot times down to something reasonable.
Edit 2: After spending a few minutes trying to swap out the drives I took the Jeda USB Hub out of the mix and things seem to work better. Will update again if there is anything worth sharing.