Post by scithen
Both trees have their perks, but honestly, I find affliction to be better for survivability - I run with a 45/5/11 build.
One could argue that the felguard with its intercept, soul link, and all of the extra +damage from demonology talents is better, but right now I'm sitting on 1037 shadow damage with fel armor and a wizard oil. I don't run anything higher than Karazhan right now, and that was only up until Shade a few times, as my tank has been needed more than my warlock.
As demo, you get fewer spells and instead have to rely on your felguard as well for supplemental damage. Granted, I leveled from 1-70 as demo, with a stint at 60 before TBC came out as I learned to drain tank. It's an efficient build, especially with the Mana Feed talent - versus mobs with mana, a demo lock (pet included) is easily completely self sufficient, even against multiple mobs. The felguard really shines in 5mans, though, where he can easily hold his own as long as he's not offtanking. Despite 9k armor and 6800 hp, my felguard could still quite easily be two- or three-shotted. I've personally never run with a demonology warlock in a raid, but I imagine in a 25man there's a bit more room for leeway. In 10mans, I find affliction to be better.
Mainly due to the extra health regen from SL and FSW (if you have it) - 2% may not be much, but it adds up. Combine that with the fact that most of our affliction spells receive full bonus from our shadow damage, and you're looking at fairly impressive damage. I don't claim to be the best at my class, but right now the only classes that can outdps me are the ones that stack crit - mages, rogues, destruction locks. Fear my 8.20% crit chance. But nine times out of ten, I'm not the one pulling from the tank and subsequently getting killed.
As for grinding while affliction: everyone has their own method, and I'm no different. I don't like taking on more than one mob (sometimes two) unless the people in my farming area are being dicks, so I usually just:
CoA, Corr, SL, and let them beat on me while the dots keep me regenning. Drain Soul at ~15% for the mana return, and keep going. Three dots is easily enough for me to kill most mobs, even if it does take 20-30 seconds. I don't kill at light speed, but it's efficient. Multi-mob grinding isn't any different, I just have to be careful - hard to drain tank level 70 non elites when they're hitting for roughly 150% of what you're bringing in via DL/SS/SL.