My answer would be: both
Get a KickROM-Switcher.
You can then install a contemporary Kick1.3 from back then AND get the recently upgraded 3.1.4.1.
I would expect that you will use Kick1.3 only every once in a while for the nice retro-Kick and use Kick/WB3.1[.x] with WHDLoad like 90% of your time.
While Kick1.3 would need to be sourced used, like, from ebay, you can still buy 3.1.4.1 new from various Amiga-shops.
Have fun,
McT