Add to Catalog vs Move to Catalog during import

Image quality: no difference how you do it.

Ease of use: it makes little difference where the images are imported AT - but this can't in practice be, on an SD card.

In this case you cannot "Add" and you cannot "Move". You can only "Copy" (to a new location, one of the storage drives either internal or external which your computer has) or else "Copy as DNG" which at the same time also converts from the original format into DNG. I recommend you leave DNG alone unless/until you identify a positive need for that - you can always convert later if desired.

So you are left with "Copy". And either LR can file the copy in a place that you exactly specify each time, or else it can take care of the filing destination for you. Many people use an automated  date-based system with year, month, day (or whatever). After LR has made the needed folder(s) and copied the images into those, you can optionally edit those folder names yourself appending some descriptive text or whatever (I don't bother; since I rely on keywords and collections only).

Incidentally, it is not "Move to Catalog" - the Catalog is not a storage location. All four import options add new entries into the Catalog's database, identically - the difference between these lies, in what happens with the associated physical file.

You can't (and shouldn't) use Add when importing from a card. Add leaves the photos where they are, and that card will get re-formatted and re-used and those images will be forever missing in Lightroom.

Copy copies the images to some place on your hard disk that you specify.