When to use Blob vs ADLS Gen2
New analytics projects should use ADLS Gen2, and current Blob storage should be converted to ADLS Gen2, unless these are non-analytical use cases that only need object storage rather than hierarchical storage (i.e. video, images, backup files), in which case you can use Blob Storage and save a bit of money on transaction costs (storage costs will be the same between Blob and ADLS Gen2 but transaction costs will be a bit higher for ADLS Gen2 due to the overhead of namespaces).
Looks like there are still some things missing from Gen2, so don’t automatically jump on an upgrade. Read the documentation first to make sure you aren’t relying on something which isn’t there yet.