Oddly enough, my experience is in agreement! For Naxx25 I was involved in a guild alliance that didn't put much thought into formalizing loot rules. Everything was /roll limited to main-spec appropriate pieces (followed by greed offspec rolls), with a limit of 1 piece per raid night until all rollers had gotten something. The slate was wiped entirely clean for every raid night.
Prior to this guild alliance forming, I had pugged some 25's a few times, and had already gotten a few drops and collected some badges. I was basically in the position of benefiting from some targeted rolls on specific pieces.
You can probably predict what happens when we roll into Naxx25 with other players of my role coming in with blues.
They win something almost every night, because everything is an upgrade. I might roll on one thing the whole week, and get beaten by someone who had already won pieces on two prior raid nights.
The net result: after about a month and a half of Naxx25 full clears, I win exactly one tier token and one epic. The other players of my role end up in full Valorous and Epic achievement. I stop attending the alliance raids and just pug, and very quickly end up getting some reasonable gear.
The moral of the story: if your guild doesn't take the time to at least think out a fair loot system, PUGs can actually be better.