You can change the icon under Bookmark style properties, and if you remove the class it defaults to text.
For fine grain changes look at the templates;
bookmarks_tab
bookmarks_tab.css
The guts of it is;
Code:
.navTabs .bookmarks .fa {
{xen:property bookmarkNavTabStyle}
}
Code:
<a href="{xen:link account/bookmarks}" rel="Menu" class="navLink NoPopupGadget"><xen:if hascontent="true"><strong><i class="<xen:contentcheck>{xen:property bookmarkNavTab}</xen:contentcheck>"></i></strong><xen:else />{xen:phrase bookmarks_bookmarks}</xen:if></a>
Thank you.
A lot complain about the pricing despite XenForo add-ons being reasonable low volume and often significant development time being put into XF add-ons.