I have Gel Spun in many of my larger flyfishing outfits because I tend to like reels slightly on the smaller side, especially in single handers. My Bauer M4SL loaded with a Rio 8wt Versitip is one example. You don't want your fingers anywhere near gel spun or braided line when a fish takes off...trust me on that. Let the drag of your reel do its job, and if you need a little more control, hopefully it has an exposed rim so you can palm it. A properly loaded large arbor reel with the right dimensions shouldn't need your finger to guide the line back on as you wind it. Reels that stack line too much often are the wide and shallow variety.
One thing about brightly coloured backing that I don't particularly like is that they often stain the end of your flyline the same colour. This is not really a big deal, as it doesn't affectg performance, but it's just a little bit annoying.
The Rio Grand is a nice line. I'm somewhat of a Rio fan myself. Matched with the right rod, you'll have no problems turning over larger/heavier flies over longer distances.