I can vouch for the Siren tank, lovely flavour response from that one. But as disco says, every tank has it's individual quirks, including the Siren. I'm also a newbie to RTAs..and have only started using the Siren, therefor still playing around with build set ups. With my Siren, i'm still getting leakage issues via the air vents...but have managed to reduce it to an intermittent wee dribble now..unlike the downpour i had with it, the first time i refilled! It practically gushed out! Turn out my coil was too close to the deck's air holes, so the wick was probably touching the deck. Fixed that...but now I have noticed that my coil has a habit of sinking down closer to the air holes, than where i had initially positioned it. Could be that the wire i'm using is too thin & perhaps distorting under fire? Dunno, But i'll get it sussed eventually.
Anyway, i digress, as far as the Siren's performance is concerned, I like it, produces a rich flavour and a draw not too disimiliar to a Nuauty Mini, just slightly more airy fully open..but nice with a 1.0 ohm build.