For my purposes in PHP coding, I have the following SNMP options set, always. These aren't documented very well in PHP's docs, but they make dealing with the SNMP results a LOT easier:
<?php
// Return back the numeric OIDs, instead of text strings.
snmp_set_oid_numeric_print(1);
// Get just the values.
snmp_set_quick_print(TRUE);
// For sequence types, return just the numbers, not the string and numbers.
snmp_set_enum_print(TRUE);
// Don't let the SNMP library get cute with value interpretation. This makes
// MAC addresses return the 6 binary bytes, timeticks to return just the integer
// value, and some other things.
snmp_set_valueretrieval(SNMP_VALUE_PLAIN);
?>