Site Name

I am the only plate wearing DPS in a 10 man. An item drops I want and I get it because I am the only plate wearing DPS.
I am one of 5 plate wearing DPS in a 25 man. An item drops I want, but I don’t get it because there are other players.

When you consider the differences this way, of course it looks much better to be in the 10 man. But, you are ignoring the TIME factor. If the item drops once in 20 kills in 10 man, but 5 times in 20 kills in 25 man, then the number of kills (ie the time) before you get the item are EXACTLY THE SAME. This does not put 25 man raids at an inherent disadvantage. (If your raid group has so many plate DPS that there is many more than 5 times the competition for items as a 10 man, it is not a very balanced group, and you have bigger problems than loot distribution.)

In cataclysm 25 man raiders are not at a gear disadvantage, 10 man raiders will face the same difficulty fights, 25 man raiders will be compensated for the logistical difficulty. Don’t use loot or difficulty or logistics as an excuse for your choice. Do 25 mans if you prefer the bigger raid size. If you prefer smaller raids, go do 10 mans.