Print from SD card vs via USB connection to a PC

Maybe it seems like a basic question but for print integrity when you print on a 3D Printer from a PC via USB, if the PC was be shut off would that kill the print? (like how a standard printer will depend on the host PC for the bulk of the Data sent for a print job). I have the option to print from an SD card as well and that's how I've been doing it so. I suspect if the gcode is fed from the SD card (much like a standard printer with expanded system memory installed would be less dependent on a host PC) that should be a safeguard to ensure a successful print. Please feel free to correct me where I am mistaken. I am planning on adding a UPS as well to avoid the unthinkable.

Yes, shutting down the PC on a USB print will stop the print. Actually, I think you can be doing an SD card print and shutting down the PC will still reset the printer. I seem to remember having that happen when my laptop went to sleep during an SD-based print.

I don't usually connect the Printer to my PC unless I'm doing some maintenance via Pronter Face. I do know being that I have SD slot on the Printer itself that I can shut off the PC without recourse. Looks like SD card is safer (albeit less convenient) but with a good UPS on the system I should be shielded from a power or data source problems for a few hours.

There are few advantages to printing directly from PC rather than from SD. Most printers will display print progress and basic temp information, so unless you have a problem with a print and need more diagnostic information, then SD card is the way to go.

Most printers accept the commands over usb 1 line of code at a time - effectively in real time. Each command is then accepted and a confirmation of correct reception sent back to the PC. Printing from SD card is similar, with the data read sequentially.

I guess only if you want to remotely monitor your printer is there a tangible benefit to printing from PC. Personally, I use an IP security camera, but of course this would not allow me to remotely kill a print. I have a family to assist me with this ;)

I find that SD card is the way to go. I'm a busy person and I move around the house a lot. Saves a lot of time and hassle :)