I was pretty surprised to see that this VST has NO reviews.
First... it's really not a poly synth. If you're trying to create some kind of beautiful melody with bell like tones - this isn't the plugin for you.
It's pretty much a one-trick pony - but what it does, it does VERY well. Dronos is designed to be a drone generator. Very simple controls, and any novice can quickly start sculpting tones. But remember, it's designed to create a drone tone. Dronos comes with portamento, so that by alternating two notes as a bass line, the tone gradually slopes up or down to the next note. I've used it with great results. It can function well against a gated synth line, as the framework for your nice stuttering rythym line and your incessant 1/4 note bass drum at 150 BPM... and if you switch to around C5 or so, it even works for your J. M. Jarre style breakdown.
Or if you're a metal head like me, it's almost fuel for the framework for a thousand songs - I almost think it shines best in this manner. But being a metal head, it was an immediate "Oh, i'm using THIS!" moment when I first heard it. That song you wanted to write about the four Vikings entering the Dragon's Lair? Crank out a nice D2 range drone, slide that up to F#, then back... your drummer should already be pounding on the toms by this point. Until Spinal Tap serves you with a cease and desist order... So that everyone is clear where I'm coming from musically, I write both Metal with a techno edge, and slower, ethereal music. This isn't perfect for everyone. But it's free, and I do recommend it.
I'm rating it at an 8 as it is indeed basically a one trick pony. But with that in mind, I love this synth.