He works

What I like the CATEYE:
The signal transmission is working properly, no minutes long synchronizing, after two revolutions of the wheel is a stable and reliable signal. The CATEYE turns, unlike the SIGMA, also itself active as soon as it detects a signal.
Attractive appearance
Easy to read display

... Less like:
The attachment of the transmitter and handlebar bracket is rather amateurishly constructed. In particular, the mounting of the transmitter with standard cable ties means that the sender does not really sit firmly on the pipe and on bumpy before slipping, which of course leads to loss of signal when the magnetic spacing is no longer correct.
Removing the display unit of the handlebar mount is not well resolved, the compound has the pushing down an extremely hard resistance point and if one has overcome, then misses (at least to me), the display unit like with swing on the hand over to the floor.
Since the display rotation and also the reset with light tapping is done on the top, it's me now already repeatedly happened that I at breaks (for map reading, telephoning, drinking) unnoticed and unintentionally, the display unit "operated" and triggered a reset of the current tour dates have.

Conclusion:
The SIGMA seemed to me in almost all aspects of installation, handling and operation more elaborate than the CATEYE, and in the knowledge that it in detail and feel better, I can give the CATEYE no Top Score.
Only the signal transmission because the CATEYE is clearly superior and this is at the end but then the killer criterion for a wireless bicycle computer. The SIGMA with the signal transmission from the CATEYE - that would be my thing.