If you don't buy an MS390 (and you should avoid them, buggy) you only have one licence option - Enterprise. So that just got easier.
Your next choice is the licence duration. Most companies go for 3 or 5 years. 5 gives you a better pricing deal. Note that if the licence expires the switch will stop working. You can of course renew the licence.
This datasheet lists all the models in a table and feature comparison.
https://meraki.cisco.com/product-collateral/ms-family-datasheet/?file