I don't know if this will help given your location, but here in the States I always comparison shop tire prices online before making a purchase. There are a number of services available, and price -- even with shipping included -- can vary widely. A quick check at this writing shows a spread of USD$59.90 with shipping to as much as USD$77.99 plus shipping. Prices can easily change within the hour.
Here are some current results for the Schwalbe Marathon Extreme 26x2.0 tires from online shopping price aggregators:http://www.google.com/search?q=schwalbe+marathon+extreme+26x2.0&tbm=shop&hl=en&aq=f#hl=en&safe=off&tbm=shop&sa=X&psj=1&ei=UcAhT8SZHqjniAK57Y3cBw&ved=0CEEQBSgA&q=schwalbe+marathon+extreme+26+x+2.0&spell=1&bav=on.2,or.r_gc.r_pw.,cf.osb&fp=d23267ce07f75cfc&biw=1296&bih=627
Either of the tires you're considering are good and well-regarded by users.
Schwalbe's site indicates cracked sidewalls can occur from underinflation ( http://www.schwalbetires.com/tech_info/inflation_pressure
If the inflation pressure is continuously too low, premature tire wear is the result. Cracking of the sidewall is the typical consequence. Abrasion is also unnecessarily high.
That might explain the Reflex tape coming loose, though I found the Netherlands' sand roads will do a good job of it too.
In my experience, time and weather (ozone and ultraviolet light) can also cause sidewall cracking. Interior casing separation and splitting can be caused by impact while underinflated at one extreme and by overinflation at the other (the casing expands beyond the less inflexible flat-protecting belt until something gives).
All the best,