Generally speaking, if you are using Scala then you must use a Standard cluster. If you are using another language then typically the high concurrency is a better option as it does a better job sharing compute with multiple users. If you are looking to create a single user cluster and only one person uses it at a time then go with Standard anyways.

Note that standard is best for single users, but it is not restricted meaning multiple users can still use a standard cluster.. not recommended.