Microsoft has made great strides it making it easy to migrate from Azure Classic (aka IaaS 1.0) to Azure Resource Manager, (aka ARM or what I consider IaaS v2.0).
At a very high level, the process involves migrating the vNet first, which automatically migrates the underlying VM’s. Then the next step is to migrate the storage accounts.
This process is straight-forward and easy to follow the step-by-step guidance in PowerShell (here) and there is a nice video walkthrough (here).
One interesting thing I observed is that the vNet, VM and Storage account will all have the “-Migrated” name appended to the end of the previously named object.
At this time it doesn’t appear possible to rename a resource group (feature request is marked as ‘pending’ on this website here).
The work-around is to create a new resource group and then migrate the migrated objects into the new group.