How updated is your Rawr? A lots changed since the first 3.0.8 (lol) came out. I would seriously venture to guess that single upgrades may be a better option over taking a notably downgraded piece of gear from 10-mans.
I have never been a fan of Heroes T7, even in 10 man Naxx you could get better in pure stat weight. The saving grace, especially for Arcane, is actually the 2-piece set which adds greater throttle control with both of its effects giving massive gains and control to Arcane - the 4 piece is less worth going after unless you're already there regardless.
Socketing optimally -
What you get from Heroes 80 Haste Rating
From 200% Critical Damage up to 205% Critical Damage
What you get from Current Epics 8 Spell Power
102 Crit Rating
14 Hit Rating
19 Int
26 Sta
3 Spi
Don't get me wrong, 80 haste is notable and the bonus crit damage is obviously a free 2.5% DPS boost for crits which probably hovers around .8% raw DPS increase. I wouldn't say either is a decisive winner one way or the other.
On top of that, if you were to pick up some better Non-set 25 man epics you would probably find yourself ahead of the game. Of the Valorous set, the Pants are generally the worst compared to other options and the Helm is the best - reflecting the difficulty in attaining it.
If the set is something you're interested in trying out you should go for it! There are MUCH better Non-T7 Chest and Leggings available, though ::
Heigan's Putrid Vestments for a Robe and
Leggings of the Instructor from 10 Man, or
Legwraps of the Defeated Dragon or
Leggings of Mortal Arrogance from 25 Man all come to mind. There are many out there.
With Arcane the 4 Piece Bonus, as nice as it is, should not be as high of a priority as stacking Spell Power, Haste and Critical Strike. As for the 2-Piece Bonus, its invaluable.
Once you can get your hands on the Valorous T7 I would scoop those up, though. They are generally the best in slot items in one way or the other!
Edited, Feb 26th 2009 2:42am by tzsjynx