I've been using the Raspberry PI setup now for a couple of months and it works like a charm. When I arrive at home the PI connects to my WiFi network and moves all Sentry Footage (SavedClips content, if any) to my Synology NAS and removes them from the PI. When completed I get a notification via Pushover. It also allows me to move music files from my NAS to the PI on the secondary partition I've created specifically for music just by putting the mp3 in a specific folder on my NAS that the PI checks for content. Never a full 'USB stick' because of Sentry. And when I arrive in the car during a trip and see a Sentry event and want to investigate, I activate the HotSpot feature on my phone with the same SSID and pw as my home environment so that I have a connection between the PI and my phone that allows me to connect to the webserver on the PI (from the phone) and view the Sentry Footage instantly. The latter function also allows me to upload the footage to my Google Drive via this hotspot. Last but not least I can also connect to the webserver on the PI when at home and view the RecentClips footage and/or upload to Google Drive (in case you think something happened recently (< last hour) and want to review.
Indeed you do need to spend some time installing the PI, but the instructions are pretty straightforward and when successful it's a real bonus feature to the car (at least for the time being until Tesla improves it's Sentry functionality).