Out of sheer boredom and curiosity, I compiled the stats of the 25 man tier 7 and 10 man tier 7 for ret to see how much you would be rewarded for romping around with 24 fellow adventurers instead of 9.
Here are the results stat differences of a ret paladin using 5/5 tier 7.25 vs. tier 7.10:
Crit Rating: +37
Haste Rating: +38
Hit Rating: +15
This is not including Gems or socket bonuses, this is just pure item stats.