In my experience, you get what you pay for at the end of the day.
Very true most of the time but why would you want to spend £100 + pounds on a battery that is slightly lighter and smaller than a 063 and costs £60 more.
My £40 063's last at least 5 years (work it out, 3 in 17 summers and the 3rd is still going strong). Based on that I think I am getting exactly what I paid for.
For these special batteries to be worth the extra money they would have to last 12 years or more, bet they don't.
But since in the current 7 world every gram counts using a battery that weighs a little more just will not be acceptable.
Having a car that starts reliably is far more important than saving a few grams, having a nice and shiny lightweight battery is not going to impress that many people when you are sat at the side of the road.