Menthol juices are usually fine.
There's a list of ingredients that cause polycarbonate plastic to basically dissolve slowly, which leads to cracking or 'fogging' of the tank section. For reasons known only to large Chinese clearomiser makers, just about everyone and their dog uses polycarbonate plastic to make clearomisers, when it's one of the worst suited materials to the job. If they used a plastic like the one juice bottles are made from then this wouldn't be a problem.
they do though, and it is.
The majority of e-liquids are fine and there's a handy list of some tank cracking e-liquids
to be found here.
The best possible material to make clearomiser tanks out of is glass. Glass is basically inert and you can use anything you like in it and it won't damage the tank. the ProTank 2 mini is the 'big brother' to the Evod is the same size and shape(ish) uses the same heads and holds the same amount of e-liquid.
Generally speaking the atomiser/clearomiser you use makes a big diffirence to the quality of the vape you get out of it.
there are 3 big steps every vaper can take to vastly improve their quality of vape.
i) stop using cigalike batteries and start using a generation2 (eGo or better) battery.
ii) stop using cheap and nasty clearomisers and use a good atomiser along with a reasonable battery.
iii) move away from the fixed voltage eGo battery and start using a variable voltage battery.
there are other jumps in vape quality to be found but they tend to get more and more expensive as you go and they typically are smaller increases in quality (law of diminishing returns)
An evod that's setup correctly running on a VV eGo battery is a night and day quality difference to a poor clearo running on a fixed voltage eGo, which in turn is lots better than the average cig-a-like
