What Are The Benefits Over The Other Materials Out There?

Ceramic Heavy and fragile, requires a kiln (highly specialized to use, expensive, and needs a dedicated space) There is a definite size limitation too. Beloved pieces randomly explode.
Paper Maché Regrettably, it will disintegrate in the presence of the morning dew. Rain is out of the question, and snow is impossible
Sculpey, Fimo, Premo, Etc. Indoor only ($$$), small figures only, less than a foot tall. Cower in fear of being left outdoors.
Epoxy/Apoxie Based Clays Epoxy is a form of plastic, a two part system where a catalyst and resin are mixed together to harden. Premium uses water instead as it's mixing agent. 
Some epoxies are mixed with talc-like fillers to bulk them out to a putty consistency. These knead-able epoxys (Apoxie, Magic Sculpt) are typically used in small and mid-sized pieces, being generally accepted as too expensive for larger work. Anything larger than a two foot figure would be preferably sculpted in clay, molded in rubber, and then cast in another material. 
Epoxy has a direct linear cure, once mixed, it begins to harden steadily and quickly to a hard finish.
Epoxies are a strong material, and a good workable putty, but don't have the consistency and nature of a traditional sculpting clay.

Pal Tiya Premium (PTP) is an outdoor self curing cement based clay. It can do modest details on small work. PTP excels at medium to large scale pieces, from 1 foot to well past human height. It's strength, weather proof properties and lower cost allow for substantially bigger sculptures. It can also be worked in subsequent sessions. Texture is a pliable dough with a two hour work time. 
Pal Tiya Premium shares the same touch and feel as a classic ceramic based clay. 
Plaster, Hydrostone, Gypsum Dissolves within a year in the weather becoming a poetic metaphor for the "Relentless Advance of Time on mortal objects".
Wood Time consuming, difficult to do subtle human figures well, repairs and alterations are difficult. (A bonus; the unsuccessful sculptures can still be used to heat the house)
Stone Time consuming, difficult. A modest sculpture can weigh as much as an engine block, mistakes are difficult to repair.
Concrete Can be very strong and can go very large. Fragile by itself, it requires steel/chicken-wire armatures. Very thin delicate-as-a-teacup details are unlikely to survive. Might need welding; see "Steel".
Bronze Are you kidding?! Out of the question! We kept tripping over the cat as we moved the 1300 C boiling metal crucible off the stove top.
Steel Needs welding equipment ($$$) and welding in my apartment is discouraged. Rusts.
Plastics Requires molds ($$$), often highly toxic, specialized equipment, The safety sheets can be scarier than Stephen King novels.
Fiberglass Toxic! ($$$) The heavy chemical smell will seriously upset your mom/ neighbors/local militia.
Darjit Pal Tiya Premium was designed to be a easy "add water and mix" product. All the work of making it weather proof, super strong, thaw resistant, and silky smooth has been done in the lab. Every component was chosen carefully to create a specific optimal mix. Darjit is made by each sculptor personally and each mix is different.
Plasticine We LOVE Plasticine. It's fun watching creations melt outside in the hot sun. "I'm Meltiinng! What a world, what a worrlld!".
Papercrete Homemade cement based paper mache includes additional materials like wood paper pulp, jointing compound and PVA. For these DIY versions, it is impossible to determine how long they will last. Each artist will make their own with available materials. Without careful testing, the results will make themselves known only by watching the sculpture for several years. Using a sealant is strongly encouraged to prevent water getting to the wood paper pulp and jointing compound.  
Pal Tiya Premium is a very strong sculpting material which works like a cement mache. It was specifically designed and tested to permanently survive extreme outdoor conditions like freezing and thawing. It is for artists who want an enduring material they can depend on for both home projects and professional commissions. It is not necessary to seal Pal Tiya Premium for outdoor use. 
Mashed Potatoes
We've found it's totally brilliant for making replicas of Devil's Tower Wyoming.