I'm an electronic engineer and can say with some authority that a correctly crimped connection is perfect, like the other reply states. BUT, I still solder all crimped connections because I can't affort the correct industrial crimping tools. The industrial ones have a replaceable insert for the crimp surface and is not made out of 2 blades of pressed sheet metal. Expect to pay $100+ second hand! Using brand name spades also helps, as they have good plating on them which is essencial when it comes to long term exposure to moisture.