We spent three weeks on Lei Shen in total. One was a fairly light raid week (third week of heroic progression) where we killed Iron Qon and Council and then put in some Lei Shen attempts. We knew we weren't killing it that week, so we took it easy, learned what we could, overhealed it to get to the transition cleanly as much as possible, worked out positioning and theorycrafted outside of raid and basically worked out our strat. The DPS checks were extremely tight and while we could definitely beat them it required a lot more precision, and a better strat, than in later weeks.
Second week we took it much more seriously, raided six days in the week as serious progression, practiced positioning and everything on normal mode, really aimed for a kill, wiped at 8% on Monday night. And then the next reset we raced through farm and killed it in 17 pulls on Wednesday night.
Method killed it before we even got to the boss, Blood Legion killed it the end of that first week we were on it, and the kill video came out after Exorsus killed it, during that second week. I can't stress enough how much pull count isn't relevant on such a hard fight. We could have raided a lot more in the first week and wiped an extra 100 times, given we were pulling 40 times a night or something at that point and having quick wipes. Would that have made us a worse guild, since our pull count would have been higher? We could also have held our pulls in week one and waited for week two and put the time in then when the dps check was easier, and probably killed it in less pulls. Again, no real relevance to our skill.
A fight one week is not the same as the next week with another reset of gear, and that is true this tier more than any other in the game given how steep gear scaling is. Our week 1 Durumu kill was 10:00 and our week 2 Durumu kill was 9:41. That's a 3% decrease in time, which doesn't sound like a lot, but it's the difference between killing it right on berserk after half a dozen sub-5% berserk wipes, and killing it the first time you get to the end of the fight with everyone alive. The first week on Lei Shen the DPS check in p1 was really tight and required perfect positioning, tanks maximising DPS, healers all DPSing during heroism etc. The second week we could do it every time as long as we didn't get any extra adds, and by the week after we killed it guilds were getting through p1 without even using hero, so they could use it with CDs at the start of p3. On our kill our tank died in p1 and the week before that would have been a wipe because of the lost vengeance. As it was, it didn't matter.
When it comes to comparing us with Method or Blood Legion, the difference between carefully planning around your raid time and potential video releases and so on vs just going for it and working out your own strat to kill it as fast as possible is too big to ignore. And the fights they do are just harder than they are later.