I would genuinely recommend you go with 512 GB storage. With 256 GB you will always find yourself having to delete stuff and running virtual machines will always require you to then delete even more to make space for them. If you were going to do just web development, 256 GB would have probably been OK, unless you’re dealing with big corporate full-stack setups, but adding mobile development on two platforms to the mix would make me feel uneasy a bit with just 256 GB. The 16 GB RAM is perfect.