For the longest time, I liked the Commando emitter for it's vented slots and slanted top. However, my one issue with it was that it has sharp corners near the base of the emitter that kept scraping the top of my thumb. (I also prefer the MK. 1 Commando with 5 vents, over the MK. 2 commando which has 6 slots.)
My favorite emitter styles are ones that have slanted tops, but prior to the Syren, I couldn't find an emitter like this with venting (Other than the Commando). So, when the Syren emitter was added, it caught my interest and I decided to get it. Just came in today, and I got to say it feels great.
The narrow neck at the base of this emitter makes it great to hold and feels natural. My index finger and thumb wrap exactly where I need them to with this emitter. Great sleek aesthetic design too.
