Years ago when first teaching self-defense with edge weapons the choice was Spyderco Endura because they fit a hand well, trainers available, affordability/price range and what many deem very important (although not me), price. In recent years, the Endura has fallen down my list while the Benchmade Griptilian is my recommendation. The Griptilian axis lock mechanism excels (in my honest opinion) over the Endura lock back lock. The Griptilian lock has never failed me while teaching but the Endura lock has failed several times on different trainers. Please note I think that Spyderco folders are a good choice for defensive purposes but prefer many Benchmade and Emerson folders to Spyderco. My top recommendations are Benchmade Griptilian regular or small size depending on the users hand size or the Emerson Commander regular or small size, same reasons as the Griptilian but would not recommend the Super Commander for the average civilian but would for someone more skilled both in the use of edge weapons and understanding the legality of such a tool.
Everyone has their likes and dislikes and this is my view on Spyderco for personal protection. Do I carry Spyderco for utility usage, yes.