What is best one available on the market today?
Not the last one I bought but probably the latest in terms of a release date is the Digiflavor Siren V4. Whilst it’s easy to build, doesn’t seem to leak and delivers decent flavour I personally wouldn’t recommend it as it’s a royal pain in the arse to try and clean.
The tank doesn’t come apart from the chamber and it’s impossible to clean inside and around it which I like to do. Basically I put water in it,shake it and leave it to air dry which isn’t ideal in my opinion. It’s also hard to determine the liquid level so FWIW that’s a non recommendation.