Hi G S S,
Thank you for your interest in our products!
I will try to answer your questions one by one:
1) What does it mean by Sitefinity integrating with RAD Controls (as in the tour/feature list)? I tried the demo and you can upload control files (.ascx etc). Wouldn't it be the same thing if I coded the functionality to import web parts?
With this we mean that we distribute the controls (Telerik.Web.UI) controls with Sitefinity. They can be used only in a Sitefinity project though, otherwise you will get a license error message. But yes, you can do what you suggested. Still, the user controls are preferred way to deploy the new functionality.
2) When you state that SiteFinity has the ability to add silverlight/asp.net controls to pages through the UI, that is only for online page creation? If I make a page in Visual Studio, I need a seperate license I assume?
No, you do not need a separate license. You can have as many physical pages, created through Visual Studio as you want, as long as they reside in the same Sitefinity project.
3) The problem I have noticed with using 3rd party providers is that the functionality, system robustness, etc is all fine, but the structure and decentralisation of features is a problem. Eg my site will have forums, blogs, etc, but some of these features will be per user. A newsletter engine will be dependent on an external newsletter engine, like CampaignMonitor. Can I extend the newsletter logic to work with an external newsletter engine?
I am not sure what part of the Newsletter module you want to use. But I am pretty sure that the answer is yes - you can use the public API of the Newsletter module and communicate with it from anywhere. You can use the module as a storage for e-mails and templates, but pass them to external application. Is that what you are looking for?
Don't hesitate to contact us if you have other questions.
the Telerik team