The team at TDLC were very helpful with our migration to Office 365 from Exchange 2007/2010 mailboxes as well as migrating users emails off-site (using OWA). They also helped us migrate some custom applications along for free using their Migration Tools toolset! We didn't have any issues during this process so I can not comment specifically about that however they are always quick in responding via email or phone when you need them quickly - it's great having someone who knows what we're doing but isn’t too senior up there making decisions which slows things down sometimes if your needs aren”'ts being met right away by another department member within an organisation / product area etc.. Take advantage of all resources available through TDC including TechAssistants; these guys know how everything works & will help guide best practices across multiple platforms like Windows 10 Mailbox sync with other cloud apps such as Sharepoint Online.