[xsl] union vs. "or" vs. contains?

[Bruce D'Arcus <bdarcus@xxxxxxxxxxxxx>]

I realize performance questions are always somewhat context-specific, 
but I wonder if there are still general rules about which of these is 
preferable?

<xsl:template match="db:section[contains($citation-class, 
'note')]/db:info">
  <xsl:copy-of select="."/>
</xsl:template>

<xsl:template match="db:section[$citation-class='note-bib']/db:info |
		db:section[$citation-class='note-nobib']/db:info">
  <xsl:copy-of select="."/>
</xsl:template>

<xsl:template match="db:section[$citation-class='note-bib' or 
'note-nobib']/db:info">
  <xsl:copy-of select="."/>
</xsl:template>

Bruce