I find the limits of raiding in guild is mechanics of the fights being tougher on boxers. Splitting one out to run off with a debuff, splitting into two groups to handle a specific mechanic or getting following toons stuck or dragged through stuff lead toon can quickly get out of. Some LFR's are same, but fewer tough mechanics there. Example of Morchok on heroic splitting into two. LFR and reg would be fine but would require your whole team on one boss and that can limit for buffs. Good luck raiding while boxing, can be done but requires some understanding from your raid friends. Strangers won't understand in many cases as has been discussed.

EDIT: I'd recommend a BH run first as mechanics are pretty straightforward there for boxers.