I would go for the heroic version of the TotC Sword. It shouldn't be that hard to get nowadays. The Ardent Guard has more EHP and is slightly faster. So if I had to choose between the two I would go for the Ardent Guard.
Besides if you're only doing 5 man dungeons there shouldn't be any difference noticeable so you can pick the sword you like best style-wise.
But if you have the rest of your gear enchanted and gemmed for effective health the Ardent Guard is the way to go.
Wer reitet so spät durch Nacht und Wind?
Es ist der Kodo mit seinem Rind.