Reel whichever way is most effective for you.
When I started flyfishing I cast right and reeled left. I live next to the ocean so I took up saltwater fishing. It took one fish to rip off a 100 yds of backing that I needed to crank back quickly to realise that I needed to use my dominant hand to crank. I can crank faster and for longer periods with my right hand. Most people who conduct test of cranking speed and endurance find this to be the case. There are exceptions of course.
Around here we do a lot sw fishing with conventional gear too. Most people crank with their dominant hand and hold the rod with the non dominant hand - even with really big fish.
Most sw flyfishers that I know crank with their dominant hand since the ability to crank fast for extended periods is so important to quickly bringing fish to hand.
Many people point out that spinning reels are usually cranked with the non dominant hand. However since the handles on spin reels usually provide a lager cranking radius compared to a flu reel, and because the gearing system for the reel allows a much faster rate of line recovery this is not a comparison of equivalent systems.
Another thing to consider is that if a right hander has a reel set up for left hand wind and the rod is in the right hand for the retrive there is a possibility that line may catch on the reel handle. when a fish is struck an heads off at 25 or 30 mph or more the loose line can jump up off the deck several feet in the air. I have been hit in the face by loops of line before they went through the guides. I have seen loops catch on reel handles anc cause a break off of the fish. I have also had loops of line catch on the handle of left hand wind reels when shooting line on the cast.
Anglers are often concerned about switching the rod between hands. In my experience this is a non issue. It takes very little time and can be done when the fish is in its initial run with no loss of control.
For me, I cast right handed and most of my gear is set up for right hand retrieve. I do still have all of my 2,3,4, and 5wt lined reels set up for left hand retrieve. Despite this mixture I have never mistakenly tried to reel from the wrong side