We finally bagged ourselves a demon last Thursday. Initially a lot of us felt that Magtheridon was unreasonable in terms of raid composition requirements, but the more we played with the fight we realized that what we thought was holding us back ... wasn't. Magtheridon seems to be one of the best encounters in the game thus far, right up there with fights like Maulgar and Netherspite. It still does suffer from some composition requirements that vex us a bit (3 warlocks?! That's crazy!) but that realistically shouldn't be a problem for most other guilds.
The only thing that seems problematic with Magtheridon's design is that the second phase of the fight is trivial, barring lag or people completely spacing out. The second time we killed all the Channelers with most of the raid alive, Magtheridon was dead. The fact that phase two ultimately comes down to lag seems a bit frustrating after a very difficult first phase. Redeeming that, though, there are strategic countermeasures you can take to prevent wiping to lag, so phase 2 isn't a complete flop I suppose -- there's still that raid coordination aspect.
In other news, we now -- as you can see -- have a new front page to go with our new forums. It's still very much a work in progress, but hopefully it'll be easier to maintain than our old one.