From the puzzling point of view, its not too difficult...once you know what shape you need to form. But the way the pieces have been cut (and I am sure there is some mathematical aspect to this...don't ask me what it is) make it a tad tricky. Quite amazing how the odd looking pieces can form a symmetrical 3D object.
Overall a really nice good quality shape-forming puzzle that is just the right level of difficulty for an Exchange Puzzle, something you can solve in minutes rather than hours. PM me if anyone wants to see the photo solution
For anyone interested, the Octassembly, is available from Bill via his Etsy puzzle shop mentioned above. And it cost US$21/-