What's the difference between Pro and Dev Tier?

Metered VPSs Pro Tier are designed for production ready customer applications and data. This tier always offers failover for the Virtual Servers can you buy. You’ll be able to take backups of your Virtual Servers. 100% uptime Metered VPSs Dev Tier are designed for non critical/development hosting. It is therefore advisable to finish the first for production environments and it is strongly advised not to use production and / or business critical applications with Dev Tier.