All the SIM cards for visitors from outside of Japan can be categorized in two types:
Prepaid SIM or Rental SIM.
Most of them use the same network from NTT Docomo.
You can summarize major differences between Prepaid SIM or Rental SIM as the followings.
Rental SIM Card
You can pre-order online and pick it up at airports,Hotels or accommodations.
Data speed is more stable than that of prepaid SIM type as providers ask to add bandwidth to major carriers when needed.
It is suitable for both a short and long stay.
Some providers give you a refund when you couldn't use the card
Differences between Prepaid SIM Card and Rental SIM Card