Looking at the 10 man drops vs the 251 set pieces, it is very clear the 10 man drops are made for DPS.
The set has 8 more agi, 47 more stam, 88 crit instead of 80 haste, 8 less ArP, and 59 less AP.
The set has 16 more agi, 26 more stam, 16 more crit, but 8 less ArP, 36 less AP, and one less socket.
The socket is still not enough to counter to lack of stam on a clear DPS piece, set up 2-0.
Finally a comparision that wowhead recognizes):
The set has 12 more agi, 51 more stam, 96 crit instead of 99 haste, 1 more ArP, but 41 less AP, and one less socket.
Same as above, the socket cannot offset the stam deficit of a DPS peice, set up 3-0.
The set has 31 more stam, 8 more ArP, 63 haste instead of 63 crit, but 8 less AP, and one less socket.
This one is a toss up. If you happen to get the scourge ones to drop you can safely use those and save your badges until if and when you need the set gloves for a set bonus.
The set has 24 more agi, 18 more stam, 80 expertise instead of 103 crit, 36 more ArP, but 47 less AP and one less socket.
This tier has a severe lack of hit and expertise compared to the past ones giving the set legs the edge.
The set and offset legs have the same amount of stam and agi, it looks like these legs are the exception to the 10-man for DPS rule. In addition, the set legs have more AP (16 more) for a change, and it trades 96 ArP on the set for 96 haste on the off-set and 80 expertise on the set legs for 72 crit on the off-set. Again though this comes at the cost of a socket which makes the off-set better for pure survivability which includes more savage defense procs because of extra crit (still not sure where the trade off comes in on this because with the less expertise you wont be hitting as much so less change to crit so this last part might be innacurate).
Not considering any 264 items, you still want 4pc simply because all the 251 drops are designed for dps. There are 3 different ways I would do this in this order:
- 4-pc with the second off-set legs gives you the best survivability
- 5-pc set gives you a significant threat boost over the above option at the cost of a socket which is probably the better option
- 4-pc set and off-set gloves if you just cannot get the off-set legs to drop (which unfortunately means once they do drop you basically wasted the badges buying the legs)