I love all these series! I'm a circle puzzle addict. I'm sure Burgo will chime in here, as he is the king of circle puzzles at the moment. You may want to look at some of the solving threads: circle puzzles here
, Bermuda Cubes here
, and Bermudaminxes here
. These are my rankings.Crazy 3x3x3 Plus:
Circle --> Jupiter --> Uranus --> Neptune --> Saturn --> Mars --> Earth [reduction to RC] --> Mercury --> Earth [reduction to CC] --> VenusCrazy Megaminxes:
Circle --> Jupiter = Uranus --> Saturn --> Mercury = Venus = Earth --> Neptune = MarsCrazy Tetrahedrons:
Earth --> Circle --> Venus = Saturn --> Jupiter = Mars --> Mercury --> Neptune --> Pluto  --> UranusCrazy Pentahedrons:
It's been so long since I solved these, I can't remember. I do remember Venus being key, though. Bermuda Cubes:
Mercury --> Venus --> Earth --> Mars --> Neptune --> Uranus --> Jupiter --> Saturn
[Outer planets all solve quite similarly.]Bermudaminxes:
Currently on my wish list
I know it can look like a huge financial investment to get all these puzzles. Thankfully, though, you can use the pieces from two circle puzzles of the same family to build others. See rline's excellent video
on this for more information. For example, if you buy a Crazy 3x3x3 Plus Venus and Saturn, you can swap pieces around and make any of the 8 planets [or a Circle Cube]. Basically, just look at the diagrams for each puzzle. Count the 1's and 0's on each. Buy two puzzles with opposite numbers. For example, in our previous example, Venus = four 0's and two 1's, whereas Saturn = four 1's and two 0's. By swapping centers around, you can now build ANY combination of 0's and 1's, and therefore all the planets.
The same will apply for the Megaminxes. There are many possible combinations here. For the Crazy Tetrahedrons, it's a bit more complicated because of the 2-faces. I think the winning combination was Venus and Uranus [see video
]. The Crazy Pentahedrons are even easier - just buying Earth can net you all the planets [see first video link].
As for what to start with, definitely do the Crazy 3x3x3 Plus series first. This will teach you the skills needed to tackle the Crazy Megaminxes. Tetrahedrons share some ideas with cubes and megaminxes, so try those next. Lastly, I'd say the Pentahedrons - they're quite unique. The Bermuda Cubes can be mixed in there are any point. I'd say buy two inner planets and one outer planet to start with. If you enjoy them, try the rest. When you feel comfortable with them, move on to the Bermudaminxes.