Crystal Insanity adds 500 to STR, AGI, INT, STA and SPI.
Im a restoration druid and the crystal gives me three usefull stats, INT, STA and SPI, the Flask gives me 1000 INT while the Crystal gives me 1500 usefull stats.
Stamina can be usefull when you are undergeared or your are doing trys to a boss and the damage is too high (like Thok the Bloodthirsty).
Its not the best of all, but it isn't old flask. In my guild, we use the crystal for the first try of the day and flask for the others (with a raid time of 2'5h), the alchemist only must use 1 flask each day because of the crystal.
Sorry for my bad english, i only want to expose that the crystal is more usefull than the people says

. The Crystal must be tagged as Old Flask or another category

.