Two weeks ago I also had a pretty good experience in terms of Archi HC. I had nothing to do on a wednesday night (my school had early weekend) and after farming rep for the Talbuks in Nagrand I decided to look up a nice group to do some bosses on heroic. I scrolled through some groups in the tool and a group named "doing all token bosses hc" showed up. Since having a full hc set is never wrong I instantly tried to get into that group. My gearscore was somewhere like 715 and I felt so happy when I got the invite. After that we waited a few minutes to build the group. While that the lead posted TS and the guild turned out to be very polite but funny and experienced as well. We started at Komrok and made our way to Mannoroth with just a few wipes. Some players left after each boss but the lead never posted the TS again when new chars joined the raid. At Mannoroth I was the only remaining stranger on their Teamspeak and besides a few words I didn't speak much since I was German and they were Brits. But when i realised that just me was left I started to talk a bit and told them how much in enjoyed the run so far and that i really liked the atmosphere of their guild. They thanked me and replied some friendly words. After Manno I thought the raid was over but they just went up to Archi without giving a damn. I was stunned because of the fact of giving me the opportunity to finally face Archi for the first time (never tried him on normal) but also because I didnt expect the raid to go this far with 50% random players. We one shot him and I recieved moose + achievement. When we downed Archi it was already 4am and I almost left the group at Soc because it was like 2am back then. I was so happy about my decision to stay with the raid til the end and thanked them so much. I added the lead's Battle Tag to have some nice chats and help each other out. This raid gave me such a mental boost that I geared my char to a ilvl at 720 and finally managed to get my ring. Since I joined a decent guild in spring 2015 and I knew they clear every content since BC I decided to chat with the raid lead to ask him if I may join their roster for mythic. We had a nice chat and because he already knew me from twink-runs I was allowed to join them. I improved my dps, got Archi HC trinket and some gear and after a few myth-raids I managed to get a ilvl of 733 and constant dps between 90k and 130k (depends on the boss and proc-luck since I am arcane). I joined them at 9/13 and experienced my first progress kill ever on Velhari. It felt so good and I owe all this these kind players from a random wednesday night raid.
tl;dr pug pays out sometimes, keep on going :)