I've been using Telerik r.a.d.controls for ASP.NET for a couple of years now and I have got to say that the controls are great, the support is fantastic and they listen to suggestions and are willing to integrate them into their products.

The r.a.d.editor is by far the best editor I've used with great browser support and is easy to integrate. I wanted to integrate the editor into someone else's software and the assistance I received was extremely good. They also seemed to be well ahead of the game with AJAX support and with there recently releases this seems to have really paid off.

If you keep an eye on their web site you will also see that the products are constantly being improved and new products keep coming out. The licensing seems very fair and one of the licenses give you the source code as well.

Actually, even if your not interested in the products its well worth visiting the site to see how much effort they have put into communication with their customers. They have forums, Telerik Points, MVP program, surveys and a code library and its all very nicely done.

If I had one very minor criticism to make it would be that there is some room for improvement in the documentation.

I have no reservations in recommending Telerik to other developers and I wish more companies were like them.