<div ng-init="limit = 150; moreShown = false">
{{text | limitTo: limit}}{{text.length > limit ? '...' : ''}}
<a ng-show="text.length > limit"
href ng-click="limit=text.length; moreShown = true"> More
</a>
<a ng-show="moreShown" href ng-click="limit=150; moreShown = false"> Less </a>
</div>