In a raid, anybody sane wants to turn off spell effects. But, of the 4 options (ALL | SELF | GROUP | NONE) only ALL and NONE actually do anything. Using /effects self and /effects group is the same as /effects all. It would be nice to see my own effects, to know when my spells hit and such.
It works sometimes and other times it doesn't. There seems to be no reason as to what makes it stop. If you leave it on prolong periods of time it's just a matter of when it stops working. It does this on my pc, my gf pc, my sisters and mother also told me it does this on theirs.