I've used so many fly lines over the years I've about lost tract ... and with the "new" marketing strategy, there have been all kinds of whistles and bells and claims ... and PRICE! And with today's corporate pea and shell game, you have to keep an eye on who sold what to whom and who owns what brand.

Let me take a couple of old brands that have been around for years and I have used for quite awhile (there are others, too, but let me just pick these two) - Cortland and Scientific Anglers. I have used Cortland for so many years I cannot remember when I first bought their line. Presently for my favorite 9' 5wt (Stillwater fly rod), I use a DT5F Cortland 444 "Peach" line. Love the line, love the color of the line, love how it casts. And quite often this is my dry fly rod.
O.K., also have a 8 1/2' 7wt rod that I refer to as my "windy river rod" (and two different rivers I use the rod on are just that) - since I can get that line ensnared on the river, plus I'm using more streamers, nymphs (and even poppers), and here I use Cortland's Fairplay line. The 444 Peach runs about $62.00 and the Fairplay $19.95. Is there a difference(?) Absolutely - but three times as much in cost(?) Open for debate. I suppose if the 444 Peach was twice the Fairplay, I'd concede, however three times as much ...?
Found the same thing with Scientific Anglers - my first S.A. fly line was an "Air Cel" - today that line would be in the neighborhood of $25.00. They also have a Mastery Series that sells for three times as much. And I would compare these lines with the Cortland Series.

Bottom line, if money is no object in your life and you got the bucks to splash around, nothing like the best. However, if I was strapped for cash because of demands for other things, that Cortland Fairplay and the S.A. Air Cel both are damn good fly lines for the money (I speak from experience). And I'm comparing them with the other lines I presently have, the Cortland 444 Peach and the S.A. Mastery.