I still have problems with my rex cube, and I have yet to solve my face turning octahedron, my 4x4 trajber's octahedron, my rubiks triamid, rubiks XV, rubiks dice, and my skewb ultimate. Oh, and the super square-1 is just plain annoying because the central drum misaligns. Oh and the square-1 because the corner pairing gets annoying.
The axis cube is hard until you get your head round it, then it's the same as a 3x3. Same with all the 3x3 shape mods - diamond cube, hexagona dipyramid, trajber's octahedron, rhombic dodecahedron, blade cube, hexagonal prism cube, corner turning octahedron etc. The only one of these I have issues with is the mastermorphix, because the edges get mixed up since they are all the same.
Please take off topic discussion off this forum. Thanks.