This was an interesting disc. I played 18 holes with it as my main driver on every hole, and it couldn't seem to make up it's mind about what it wanted to do.  Sometimes, it was pretty overstable, crashing in a bit over 300 feet. But when I threw it into the slightest headwind, it would turn over and never come back, it would glide forever. I got a good 400 foot through with this disc just flipping over and sailing to the right the whole time.

When thrown with moderate power it was a bit more reliable, popping up, going straight, and fading back, as the flight numbers here might suggest. However, with high power, it was pretty unpredictable- sometimes having late turn over in it's flight. 

I feel like if you're a lower arm speed player, it could be a great reliable fairway driver that hooks in at 300 feet everytime, but if you're a bigger arm player you might have a harder time figuring out what this thing really does.

That being said, it feels pretty good in the hand. This blend of Evolution is among the best I've felt. Maybe if I played with this disc more it I could figure it out and put it to use, but I have to decide if I really want to do that.

First of all, I have no idea how Gateway's flight numbers work. They called the Siren a glide 9, which obviously isn't in sync with numbers by Innova or Trilogy, and I'm guessing they're not even trying to sync with those. So, let's say that there is a scaled from 1 to 20 on glide, then 9 would be about right. The Siren is for strong throwers, and even then, you're not going to be bombing this disc for huge distances, because she wants to turn before too long. It is something of a meat hook. I'd say it is more of an overstable fairway driver.  Throw it as hard as you want, but don't expect it to glide out for much more than 300 feet tops, unless you're a beastly thrower and put some anhyzer on it.

The small bead on a wide-rim driver is a bit strange, but it didn't bother me. I enjoyed throwing the Siren and once I knew what it was, I was able to guide it on the path I wanted. I could not use it on anything remotely like a tunnel shot or anhyzer shot, but if I wanted a controlled turn at moderate distance, it worked fine in those situations. My favorite throw with the Siren was a high hyzer shot to get up and around some tall trees. The disc sunk nearly 2 inches into the soft ground upon landing for a great-looking tombstone. 

All in all, I'd call the Siren a very useful utility disc for your moderate distance, overstable needs. It lands somewhere in between a Discraft Predator and a Nuke. I felt it was something like a RDG Tyrant, though I like the Tyrant plastic better. This Evolution plastic is durable and felt something like Elite Z or Champion, though not translucent like those. Gateway's plastics can be a bit unpredictable. Evolution can feel different from one disc to the next, just like their soft putter blends are difficult to distinguish one from another, from batch to batch, in my opinion. You have to feel the discs individually to find the one that's just right for you.

I'm going to give this disc my own number ratings, based on my test throws. More like a 9, 4, -1, 4

Gateway molded discs just don't look as fine or professional looking as discs by other manufacturers. The 175g Blue Siren I have has some excess flashing sticking out of it that make it look pretty sloppy for a brand new disc. I've thrown other Gateway Evolution plastic discs before, but this particular blend on the Siren feels a lot different than others I've felt. This Evolution version is more Starlike than Champion like.

I am not a big arm player, and I live at a high altitude (which makes discs more overstable). For me, the Siren was nothing like the stated ratings, but was very overstable for me. Thrown backhand, I couldn't get the Siren out past 300 feet unless I released it on an Anhyzer and let it flex out. Where I did like the Siren was for forehand throws. This disc is the perfect stability for me for distance sidearm throws. Flicked flat it turns a little for me, flexes out and fades nicely to the right at the end of flight. I'm able to flick the Siren about 330 feet when I do it correctly.

To me this is just an average disc. It kind of has an interesting bead on it, but I didn't notice it at all while throwing either forehand or backhand. The one thing I really like about my Siren is that it has a nice big Infinite Bomber stamp that is pretty cool.