I have found no difference zwichen series 29xx and 31xx this. Have decided to use the 31xx series, because here no one has written about failures. AND - the Model 31xx is in the Top 100 sales, whereas the Model 29xx is not in the list.
Possibly, these are a product of the care model and the 31xx series is "improved".
to all the long-term deficiencies of course I can not say anything yet.
Overall, the shoe makes a solid impression. No abnormalities of the joints, transitions. No evidence of the occurrence of fissures, cracks, etc.