I'm using the UWP controls of Syncfusion. Most of the controls are very usefull.
For me, DataGrid, the Chart Controls and the MS-Office (Excel, Word) libraries are the absolute highlights.
Why? Firstly they are well documented, you get an Visual Studio Project with full access to the examples.
The Datagrid ist completely costomizeable .
The Charts: There is any chart you need , and the chart controls are very intuitively .
The Excel Library is in my opinion the best in the market. Most applications need export top word or Excel and
this Library is realy amazing.
The Service is top: I had problems with the Schedule Control, and used the community version
of their Product in a private project (so didn't expect much help) .
And they helped me very competently and effectively.
I compared it with Telerik and some other products. I made a Prototype with each of the Libraries I could get. I think in direct comparison you surely will see the high quality of this controls.
They also have a rich portfolio of JScript/HTML ( modern Architecture Angular etc.) Controls, ETL and Reporting Controls.