With Bert, a cool traveler I met in Tokyo a few weeks ago
I’ve never been to Haarlem before but would recommend it. Only 18 minutes by frequent commuter train (€3.90 each way, just like the airport, with free Wi-Fi to boot). Note at Amsterdam Centraal it leaves from platform 1 which is not well signed – you have to go towards the west end of platform 2a to find it.
Lots of budding musicians there, easier vibe, less expensive/touristy but not a late night party town (for those that care)