Nowadays I feel new school especially digital is the way to go. You can get far more value for your buck and the possibilities are endless. However If you do have the money and understand the machines old school synths can be unique and bring a certain presence you might not be able to fully recreate digitally.
I think that old school synthesizers have such a unique sound to offer. There's something about the user experience that is aesthetically pleasing, and yet modern synthesizers offer so many unique features and customizations to really dial in the specific sounds you enjoy. Overall, I would say that modern synthesizers are what I prefer to play!