I've used Syncfusion products quite a few times over the years. Most recently with Essential Studio for ASP.NET MVC. I'm primarily using the tools (tree view, WYSIWYG editor, and some others). My options were develop our own, use open source, or buy commercial software. I like OSS, but we sometimes have clients with strict restrictions on what we can use in our products. On top of that you don't know what kind of support you will get with OSS. I didn't have time to develop our own, so we went the commercial route. I compared quite a few and Syncfusion is what we went with based on evaluation new products and our past experience. Their products have always been good and, just as importantly, support has always been great. When you run into an issue it's nice knowing there is a support team that will get back to you quickly.