Got my Spark this weekend and wanted to give a little summary on it.
First off, I got a 175g Orange Spark. From the reviews posted I expected a pretty stable flight. I was not disappointed. I throw RHBH max distance around 410 ft. I would not say it was unusable over stability. I have thrown Firebirds, XXX, Felons, and Predators. I would put it in that category. When I first felt the disc I noticed it was VERY comfortable in my hand. I currently have Felon's in the bag, but their rim is wider by a small margin, but the thing with the Spark is it has a very comfortable rim depth. The felon is taller in my opinion. The OPTO plastic is amazing, very grippy but not too floppy. It has much more give then my 167g Lucid Felon. The dome was flat, but had a bit of a rise to it. Nothing like those rock hard FAF Firebirds. This was just a good ole flat disc.
The flight of the disc is a very good straight flight with a pronounced fade at the end. I would not put it in the same category as my old FLX Pred which was basically a meat hook and I only used it for trick shots. The Spark is very useable. I somewhat feel it was similar to what people are looking for in the good old Firebirds. It had very little (maybe -.25) turn, and a very pronounced 3-4 fade at the end 20-25 percent of the flight. I could depend on the LSS fade at the end and it consistently faded around the same spot every time.
Compared to the Felon, it is shorter and less stable for me. I feel the Felon is longer more of a speed 9 but the glide makes it feel like a driver distance. Because of the Sparks rim being smaller, the flight was more of longer fairway driver maybe closer to a PD or a glidey Firebird. Very useable for that OS fairway spot. I feel when it beats in it will be closer to more a broken in Firebird which will be amazing.
Conclusion: Great OS long fairway driver. Great glide and a pronounced fade. Does not immediately want to go to the left (RHBH). Very useable and will beat in nicely. Similar to the Felon, but not as long and not as much fade. More testing for me is needed, and it might take over the Felon's spot, mainly because it is more of a fairway and not a driver distance. HSS: 0 (maybe a minuscule bit of turn) LSS: 3-4