The Rhombic Dodecahedron is essentially the same puzzle, so it belongs in this discussion.
I don't have the Oct II but I do have the RD, so this is my solving outline for the RD.
1. Solve centers (like a 4x4x4, when I talk about centers I'm referring to a completed "center" being made up of the correct 4 pieces which each of which have 2 stickers on them)
a. First I solve the 4 corners (the 3-sided pyramids) on my "top" face (top being whichever face I choose first). I do this not because it's essential but because it helps me know which colours to start solving the centers by. [eg. solve the corners red blue orange, red grey green, grey yellow lilac, lilac blue white.]
b. Solve the top center. [eg. red green lilac blue]. This is done in the same sort of way as a 4x4x4 cube but obviously attention is paid to the colours. Each piece has its specific position.
c. Solve opposite center, again like I would for the 4x4x4.
d. Solve remaining centers as for a 4x4x4.
e. If I get down to 2 or 3 center pieces out of position, I use U r U' l' U r' U' l to pure cycle center pieces UBL->FUL->FUR.
2. Make edge pairs. Done the same as for a 4x4x4, by bringing edges together (disrupting centers), moving them onto a different face and then returning centers.
3. Place paired edges.
a.Same as 4x4x4, and making sure not to disturb the centers.
b. If I need to swap two edges, I do this as I would for a 4x4x4. This process is simple but difficult to explain.
4. Place corners. Using U R U' L' U R' U' L to pure cycle FUL->UBR->UBL.
By far, the most annoying/difficult part of this puzzle is getting the centers. Once they're done, the rest is fine. It took me a fair while to get my head around the solving method to adopt and I sort of avoided this puzzle for a while, but once I started "seeing" it, it made a lot more sense and I ended up enjoying the puzzle.
I did make a video of it all at my blog