inexorable sabatons vs. tempered titansteel trads

I already have TTT equipped, and I just got IS - woot! I'm mainly a secondary OT, so I'm wondering if I should equip IS boots, and if so what gem. If I put stam or stam/def, then wouldn't it be about even and duplicative of my TTT's which I'm gonna keep?

I have all def I need via trinkets, etc., but if I put more def here, then I can switch things up.

So, my question is: if you already had TTT, would you equip IS and if so (in an ideal world) how would you gem and enchant IS if you kept both?

http://www.wowhead.com/?item=39717
8def/12sta gem imo.
Comparing those boots with http://www.wowhead.com/?item=41392
you would gain:
29 Str
39 Armor
77 Block Value
33 Block Rating
and loose
39 Sta
3 Def

The BV is huge on IS boots, however i think TTT would win in a MTrole.
Id use them both, situationally.
If your the guilds second OT (would make you... 3rd tank)
I'd def. go for IS boots, since a bit less sta when OTing wont kill you.

(links makes it much easier ^^)
_________________
"It's difficult to work in a group when you're omnipotent."

Situational gear is... Situational.