Again, with geared GS'es, I've never seen them take out other decently geared people in one-hit, even with FB. If you're taking out the noobs, it doesn't really matter anyway.
I've always favored a guild with a few members who know what they're doing rather than big guilds with newbies. Each of my guild's 3 SinXes can actually solo clear some 10+ player guilds. Granted that we are extremely geared in comparison :X Not that I look down on newbs, no. If I'm free, I'll still help them on their way to becoming better players.
@ASFC: Bleh. Not everyone has Pneuma. And good Snipers can find ways around it, or move to a different target. Not saying that good Snipers are plentiful, though.