We all are always looking for some good third party controls. I had some experience with infragistics control and two years back, they use to suck bad, completely refusing to work in a shared hosting environment. So at that time, when we developed one of our website and deployed it on a share hosting account, every page with an infragistics control crashed, as they all required full trust, which would never be available in a shared hosting environment. After a long exchange of emails with the infragistics team, who continued to advise us to talk to our hosting provider, we concluded that we need to remove infragistics completely from the application and eventually write all the controls by ourselves. No need to mention that never again did we touch infragistics.
And then I came across obout controls, which are actually very good though they need to be a bit better in terms of programming integration, eg. their slide controls can get better if they provide some property like DataSource and a simple binding could do the job instead of running a foreach loop on the datasource and doing the dirty work.
They have a long range of products including tree view, calendar, HTML editor, fly outs, slide show alongwith a very rich set of tutorials. They provide about one month free trial and some of their products are completely free. Highly recommended.
