Hi Gangadhar,
Well , I think SAP CRM's WebUI is very friendly for users but it could be a new thing for users who are used to the GUI of ECC etc.
I suggest you can also go through the specs and features of SAP CustomerOnDemand but that in whole is a totally different concept , which includes cloud , mobile and an extremely good interface for users . It can connect directly with SAP ECC or CRM .
Other options include using Salesforce with SAP CRM( not recommended though).Though are a lot of points like security , integrity etc. which can be covered best with SAP CRM WebUI only. Salesforce is a third party software which depends totally on Web-Services and hence a lack of security.
/Hasan