The short answer is - it depends! It's all about personal preference. If you like bright flavours and high crunch factor, you'll like eating it straight away. If you're a fan of rich umami flavours and sour notes, allowing the radish to really take on the flavours of the seasoning, then be patient and wait those couple of days before you start eating it. If it's your first time trying it, eat a piece at every stage of the development to see what you like. You may even find you prefer it in dish amongst other flavours rather than as a side dish. It's entirely up to you!