Angular ng-switch with boolean
If you are just checking for true values, ng-if seems more appropriate and reduces the need for additional divs containing the code, reducing your sample too:
<div ng-if="Item.ItemDetails.IsNew">
<p class="new fontsize9 fontWeightBold">NEW</p>
</div>
<div class="featured" ng-if="Item.ItemDetails.IsFeatured">
<p class="fontWeightBold fontsize8">featured</p>
</div>
Full docs at: http://docs.angularjs.org/api/ng.directive:ngIf
Convert the boolean to a string:
<div ng-switch="Item.ItemDetails.IsNew.toString()">
<div ng-switch-when="true">