I love how easy it was for me or my team members to set up this service! So far we haven't had any issues with Core Group's customer support department; they have been very responsive in getting us all setup correctly via their website/support site.
They also help keep everything well organized so that you don't run into problems later down the road if there are documents floating around without an owner (or title). We've used them as part of an initial onboarding process when setting up new employees within organizations before having access through SharePoint Online - which has helped ease some pain points associated with managing multiple users across different companies who may not always be familiar with each other but want similar tools at their disposal.