Oh Also I should mention Aspire makes their tanks in -S versions. For instance Et-s, Ce5-s, vivi nova-s. These tanks have metal housing and only a little plastic in the middle so you can see how much liquid you have left. The regular ones have plastic housing. The -S versions perform amazingly and because its full metal they dont heat up as much as so they degrade much less.
I only have the plastic ones (cause im a nitty) over 5 months now, and they are amazing!