The guild I'm in just does /roll and there's somewhat of a "loot council" that decides who gets a piece if there's competition for it. 10 man loot distribution is much simpler than 25 man(obviously) and most 10 man guilds are tightly knit enough that sharing isn't an issue.
I've been in 25 man guilds with loot council distribution where they claim it's "fair" but in reality they distributed by officer > veteran raiders > newer raiders > trials.
I was in this one guild where I spanked their resident resto shaman ALL the time and even after I was promoted to raider, he got priority on mail gear before me. The only time I got mail gear is if he already had the item or was "nice enough" to pass it to me. That sort of loot distribution is based more on favoritism/seniority and is BS imo.
I was a loot council officer back during Wrath in a 25 man guild and I think we handled loot distribution fairly. If there was a highly desired piece that drops, we would consider performance, attendance, attitude, size of upgrade, how long it had been since someone had gotten loot...if all that ended up being even between 2 solid raiders, we would have them roll off, which it didn't come to very often.
Bottom line, loot council DOES work if you have a fair team of officers distributing. I've always hated favoritism, as everyone in a raid kills a boss together and deserves a fair shot at loot, as long as they've been showing up and doing their jobs well.