Tanks = Cheap plastic. Tanks might seem like a good idea to some, however, China has yet to invest in chemical resistant plastics for their tanks as it's considerably more expensive than the plastic they're using. They hype it up to the vendors, the vendors buy tons, hype it up to you and voila, the complaints ensue and the vendor is stuck with the reputation that rightfully belongs to the cheap Chinese who only care about making maximum dollar and keeping overhead down.
If it's really important to see the liquid in the fill material from the outside, sadly, you should also become accustomed to cracking, breaking, leaking, etc., etc., etc.
I guess with how I'm vaping, it was easy for me to begin to get wrapped up in the "next big thing" China is dumping on us every month, until my sensibility kicked in and I really had to think "how important is it to have that?" "Is this practical?" "does this increase portability?" and on, and on. Finally, I just settled into basic stuff, because really, it's not about getting caught up in a trend, it's about keeping it simple and just very much enjoying using a product that's kept me away from the coffin nails for....eh, see below.
