Hey Jaz. I believe the thread is referencing building a tub surround not a shower.
Building a tub surround is an easy process made more difficult with the use of Kerdi in my opinion except for us tile men. Here in Vancouver I waterproof showers, tub surrounds and stand alone baths every week.
Denshield is fine for a tub surround but you need to insure the screw heads, seams and most importantly the bottom connection get covered with something waterproof.
Liquid membranes like those made from Mapei, Custom, Wedi and Laticrete work very well and are far easier to instal than Kerdi.
An average pail of liquid membrane will give you 60 square feet of coverage with two coats. An average tub surround measure 55 square feet of coverage needed.
We purchase our liquid membrane for about $70.00 and this little investment (plus a paint brush) can make an ordinary build stand the test of time.
Jaz Man is a huge Kerdi fan and Kerdi can do an exceptional job at waterproofing a tub but it limits your choice in setting material to non-modified thin-sets. These preform poorly compared to modified thin-sets but if your looking for "Cheap" setting materials your good to go.
We find that most tile companies require modified thin-sets. If you like the idea of a sheet membrane then working with a product like Noble Seal TS is the way to go. With Noble Seal TS you get sheet membrane science and the full spectrum of thin-sets to work with.
In Vancouver we like to board with Cement Board, Hardie Board or Green E-Board. I never hang Denshield, regular moisture resistant drywall or drywall in any shower project or tub surround setting. That said many builders still love it.