I'll throw together some other match-ups later. I did a quick run vs Death Knights and Reanimates (both vanilla, but regen added for reanimates). Both times, Rune Golems were on top greater than 50% for relatively even matchups. Now this is still a simple simulation mind you. Upgrades will be added after I get the command dials in.
One game I had a 2x3 Death Knight unit that got into a sticky situation. Engaged with Hawthorne, then 2 single Rune Golems came in flanking. They locked up the Death Knights pretty hard. Granted the Death Knights took an amazing amount of punishment, 3-4 rounds with all 3 beating on them, but the Rune Golems definitely are scary flankers.