If one was to spray a deck using oil base instead of brushing does it make a difference in the quality?
Yes it does. Deck stains don't penetrate as well when sprayed. Personally, I think spraying lattice, pickets or a fence is fine but the floor should be brushed.
Using a brush helps push the stain into the wood. Most manufactures recommend brushing.
Neither is better if either is applied according to manufactures recommended coverage per square foot (or in your case per square meter.)
Application too heavy will allow the stain to act more like a varnish and subsequently peel while too thin and the duration of the coating will be too short.