I always rip at the native resolution. To be honest, it probably makes little difference these days, but it means a smaller file size and it just feels right maintaining the original resolution and let the source, or better still, the display, do the upscaling. That said, I use StaxRip (with NVidia hardware encoding) and on the occasions I've changed resolution (admittedly usually downscaling stuff the kids want to watch), it's made a great job of it.
I would want to have my video (and audio) untouched, and let the TV upscale. If you convert then it's stuck with that quality. I use MakeMKV, you can choose to rip only the movie and deselect all unwanted audio or subtitle tracks.
MakeMKV is really the best method as it doesn't re-encode or do anything to the quality. Quality In = Quality Out. Same with size. I've used it to repackage all my DVD's and Blu ray discs to MKV. It's worth buying a license to support the author rather than having to update the registration every 3 months.
