If megafolders are legal carries in your jurisdiction, then go for the Sifu. It is by all means the biggest, meanest folder available, bar none! As to the 710 vs. Carnivour question, I don't have a 710, but I do have a Carnivour and a 720 and they are equally smooth and solid. The 720 is a bit smaller than a 710 so I can't compare in size. The blades on both seem equally sell heat-treated, an important matter with ATS34. My guess is that REKAT has beaten their QC problems, if my two REKATS are examples.
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Walk in the Light,
Hugh Fuller