Couture Tanks?

So after all that research I did on tanks the other day, I was suddenly struck by how ridiculously expensive some of the plain tanks were! Check this out:

These two from YaYa for example costs $58 and $49 respectively. The reason for the discrepancy in price here from the same brand is because the one on the left is longer and is a cashmere blend while the black one is shorter and merely cotton- sounds reasonable. A cashmere blend definitely deserves to be more expensive. But appearance wise they DO look very similar.

Then there is this grey tank from T (which I've never heard of) for $51 and this brown tank from Vince for $40. No especially expensive material here.

Next there is the unfinished edge tank (left) from Joie for $48 (at least there is SOME design) and orange tank from Adam + Eve for $42.

Usually I can appreciate and love the difference between the expensive and the cheap. But in this case, I really cannot see why. Do you? Above are two almost identical white tanks. One is $14.50 and one is $55. Which one is the couture tank? (I'll post the answer in the comments later today)