They both have their place. If you are in an area that is prone to a lot of snow, I'd say shrink wrap since it's less likely to sag under snow load, most of it will slide right off with the wrap being slick. Most shrink wrap is a one time use where the cover is multiple times over years. With a cover, it can be put on and taken off many times, pretty much anytime you want to cover it.
I use mine here at home when It's not in the warehouse stored indoors out of the weather. Been caught at home with just a light snow and it did fine.