As Ireland's broadband is not great, It is normally impossible to migrate a 20 user and upwards site over a weekend.
As the Irish Market is mostly SMB the majority of businesses have standard ADSL Connections with a 512kbps upload speed. Most businesses do not need a large upload speed but the upload speed is critical when migrating to Exchange online.
A 2gb mailbox took 5 hours to migrate over a 512kbps connection.
The reason I am posting this is to help people plan a migration properly.
Each time I have done a 40 user and upwards exchange on premise to exchange online migration I have had the benefit of having a minimum of 20Mbps Fiber Synchronous connection , which makes a hugh difference.But not every one will have a synchronous 20Mbps Fiber connection and may have to do with a standard dsl connection.