Is there any advantage/downfalls between using the inline write tag instead of the resource tag? Example:
<%=Resources.Site.SampleString %>
The resources tag (expression tag) as seen in any MSDN example:
<asp:Literal id="Literal1" runat="server" text="<%$ Resources:Site, SampleString %>" />
I find the first option far easier to use, and it has IntelliSense, but maybe it won't function the same?
These methods will function exactly the same. The latter simply calls first one; there is a reason why strongly-typed resources access code is being generated in the background. Therefore you can use whatever method you please.
By the way, there is also another way - by using meta:resourcekey attribute. So you should be able to write:
<asp:Literal id="Literal1" runat="server"
meta:resourcekey="SampleString" text="Default one" />
and it all should work exactly the same.
EDIT on implicit Localization.
What I forgot to mention, is that with meta:resourcekey certain conditions have to be met. The conditions are: