There’s a ton of new glass rods from a host of blank makers out there and you can spend a bundle on some. http://www.ginkandgasoline.com/fly-fishing-gear/graphite-vs-fiberglass-with-tim-rajeff-video/
The link has a video with some of the differences between glass and graphite. I fish both materials, but primarily fish Glass for bass and other warm freshwater fish and use glass a lot for inshore saltwater fish. I feel like I have great control in short to medium casting ranges with my glass rods. I can hold the rod longer in load with longer, slower casting strokes and feel the load better to make adjustments to the cast during the cast. A fast carbon rod would have already unloaded in the same time span. A slower glass rod is just relaxing to cast for long periods, at least for me.
Glass rods handle big or small fish well and are much harder to break when the fish dives under the boat or kayak or makes other strong moves. They tend to be shorter and that makes them good in places with cover or other space restrictions. They protect tippet better. The handle abuse better, like a strike from a lead head or tungsten bead.
I have trouble casting my glass well in windy conditions so that’s typically when I turn to fast graphite. My graphite rods are very fast and that helps me handle the wind. Graphite is also lighter and makers can build strong, long and powerful graphite rods that swing light in the hand when a glass rod of the same length and line weight rating would swing and feel and be a lot heavier. Graphite excels at mending and line control on the water. I don’t think the best glass rods can compete with the best graphite rods on casting distance all other things being equal.
There’s a whole lot of ways to get things done in casting and fly fishing and a lot comes down to personal preferences. I look at the best graphite rods excelling at distance casting, wind handling and line control, especially on the water mends. If you want or need a rod longer than 8’ or so, think graphite. If you need close in distance feel and fish in tight places and like the bend, consider glass. But either material can handle a variety of needs, I guess it comes down to what you value the most.