Build it Yourself
When building everything from scratch, there is a definite feeling of accomplishment that comes with knowing everything in the application has been custom tailored by you and your team, but what is the real price of this?  For starters, after a few days you might have the basics to display data in your custom data grid, but what about sorting, filtering, grouping, hierarchy, row details… the list goes on and on.  The time involved in developing a control like a data grid could instead be spent putting the polish on a finished application, not to mention having to bring a designer on board (assuming most clients don’t want to only see the out-of-the-box look of the core Silverlight controls) to give your application the look and feel that will wow a potential client.  And this is just one control- what happens if the client also wants data visualization, scheduling, or dynamic next-generation layouts? 

Silverlight Toolkit
The next step is obvious- use controls that someone else made.  Microsoft has actually done a great job at providing a basic suite of tools in the Silverlight Toolkit and has made strides in providing for an aggressive release schedule.  So with the toolkit you have your Data Grid, so that problem is solved.  You can also find basic controls like a Chart, a Calendar, and a TreeView.  After starting to include these in your toolbox you can start more rapidly developing your application, so now you’re on the path to quickly creating a RIA for your client.  The toolkit, however, is broken down into bands- Mature, Stable, Preview, and Experimental, with most components not in the Mature level.  This means that to include these you are taking a certain risk, as the control your client most likes may be at Preview and may stay in Preview in the next release.  Not to mention that should you encounter an issue with one of these controls, you need to rely on the greater community to support you, which means you could be on your own for solving an issue or perhaps you will create a workaround that gets broken with the next release.  You want to have confidence in the tools you are using and be confident that the issues you have with them will be addressed quickly, not only for your own sake but for the sake of the clients who are paying your bills.

Telerik RadControls for Silverlight
In most cases, the choice to utilize tools from a 3rd party vendor is pretty easy for a consultant or development shop.  They realize that the time it takes to create rich, versatile, and well styled controls can often eat away at a project, and the more projects you can successfully complete the more successful you are as a company.  When choosing Telerik, you know the hard work of developing and thoroughly testing has been completed by our development and QA teams and that you have a versatile suite to use that covers most business scenarios, with themes designed to fit any LOB application.  With that in mind, we can explore a bit more about why you should choose Telerik for your Silverlight RIA development.