Almost all fly reels of this today and time operate on a 1:1 ratio, simply meaning that one revolution of the spool will release or retrive a length of line equal to the circumference to the boundary line on the reel's spool. Obviously the exact length will vary depending on whether the reel is fully loaded or almost empty. On a conventional fly reel, the length can get diown to as little as an inch as the line reaches the arbor. Importantly, the amount of drag being applied to the line is also being artifically increased as the line nears the spool's center. That easily becomes a big problem.
Loop, the Swedish reel manufacturer, pioneered the large arbor reel to (1) alleviate the problem of drag consistency, (2) minimize startup inertia, and (3) increase retrieval speed. The large arbor, offset as it is from the reel’s spindle, quite naturally retrieves or releases more line in a single turn than that possible with a conventional fly reel. The trouble is, to carry the same amount of backing as a conventional fly reel, the large-arbor has to have a greater diameter and a spool configured with greater width and shallow line cavity. If it doesn’t, the backing capacity is sacrificed.
Like most things designed and developed to solve problems, the large arbor reel isn’t a perfect solution. It creates as many as it solves. There is a practical limit to the width of the spool. In fact, the wider the spool, the more difficult it becomes to lay the line smoothly and equally during the retrieval process, especially in a battle with Friend Fish. To bad there isn't a level wind avalable.
With this background the time has come for bias and opinion. If I were chasing steelhead, permit, bones, or Jaws, The Great White, I would want a large arbor to counter the drag effect. Somewhat assured that Friend Fish will get into my backing, tt's my belief that the middle of a fight is not the time to have to adjust the drag. For a largemouth bass, trout, redfish, and sea trout, I much prefer a conventional reel.
Being of the view that fish suitable to the lighter rod weights, such as the 5, are not likely to get into the backing -- at least not far. In my view, that sort of sets aside the argument for the large arbor reel.
Trust me, the large arbor fad will wane and a new breed of mulitpliers will hit the market proclaimed to be the greatest thing in fly fishing since the tree branch or the vine.