So for the most part everything just got a steady gain in stats, except +hit rating took a fall.

sources:
for S2 : http://www.wowhead.com/?search=merci...ladiator+plate
for S3 : http://www.worldofraids.com/news/oct...na/warrior.jpg

I'm gonna just give straight differences since you can see the pieces on your own from the above links.

Helm:
+98 Armor
+4 strength
+7 stamina
-2 hit rating
+4 critical strike rating
0 resilience change
+84 armor penetration

Gloves:
+76 Armor
+4 strength
+6 stamina
+3 critical strike rating
0 resilience change
same hamstring -3 rage effect

Chest:
+121 Armor
+4 strength
+7 stamina
-2 hit rating
+4 critical strike rating
0 resilience change
+84 armor penetration

Legs:
+106 Armor
+4 strength
+7 stamina
-2 hit rating
+4 critical strike rating
0 resilience change
+84 Armor penetration

Shoulders:
+91 Armor
+4 Strength
+6 Stamina
+3 Critical Strike rating
0 resilience change.
REQUIRES 2000 personal arena rating.

TOTAL change:
Armor: +492
Strength: +20
Stamina: +33
Hit Rating: -6
Critical Strike Rating: +18
Resilience: No change
Armor Penetration: +252

Not bad overall, same set bonuses as before.