PaaS (Disadvantages)
No Control over the VM or processing of data, this is a big security risk as you don’t know what’s happening with your data.
Possibly no control over platform depending on Cloud provider.
Platform is most likely a shared platform, for example there could be other customers running different websites on the same IIS platform.
Management task can become time consuming and tedious as you are responsible for updates and upgrades of application.
Not as cost effective as SaaS and not as much control over VM as IaaS.
IaaS (Advantages)
Customers have full control over their VM and everything inside it; customers can choose to automate the provisioning or build their own VM.
A customer can run anything they want inside their VM.
Full control of processing inside VM.
Simplifies Integration with enterprise infrastructure
Potential the most secure Cloud service using a PuC due to greater control of VM.
The customer in essence can run and control its own virtual infrastructure without the overheads of cost and maintenance from running its own hardware.