Attempted some LFR over the weekend just to see how it functioned. Thought I'd share my 1st impressions:

The raid group filled incredibly quickly, the break down of 2 tank, 6 heal, 17 DPS probably suits the demographic of players quite well.

We queued into the 1st boss of Dragon Soul and actually had some half decent attempts at killing the boss. The bosses are debuffed with a specific "essence of dragon soul" which apparently reduces their dmg/hp etc by around 25% from normal mode.

We did lose about 5 people every wipe, which is probably partially a symptom of PTR, but regardless they can be replaced pretty quickly with the raid finder tool. We seemed to have unlimited kicks, for dc'd people at least.

Basically it boiled down to a regular pug with simple player awareness (or lack of) preventing a kill. I imagine after a few weeks LFR groups should probably be relatively successful.