Howdy,
I recently came back from a pretty long break to find some cool new stuff like this spell. I solo/box a Druid and BL or Monk. I don't know about how handy this is in a guild/raiding effort, but for solo/boxing it is awesome! I have had to use this a couple times now and it saved me a lot of time running back to where ever I was camping etc. 90% is pretty respectable and as previously mentioned by Nethor, the actual difference between the 90% & 96% rez is not much. I can get that extra 6% of the lost experience back (and a lot more) in the time it would have taken me to (A) summon my corpse, (B) get a rez, (C) and run back to my camp.
~Qinju