There shouldn't be styling issues mixing components from our UI for ASP.NET AJAX and UI for ASP.NET MVC suites in the same application. Note that they use similar general concepts for applying styles, however the actual mechanism/framework which manages these styles has some specifics in the two suites.
You can find more information about the common styling paradigm in Kendo UI here:
while for UI for ASP.NET AJAX you can search in each individual widget's documentation:
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