ionice to make vacuum friendier?

Seems Linux has IO scheduling through a program called ionice.

Has anyone here experimented with using it rather than
vacuum sleep settings?

http://linux.die.net/man/1/ionice
   This program sets the io scheduling class and priority
   for a program. As of this writing, Linux supports 3 scheduling
   classes:

   Idle. A program running with idle io priority will only get disk
   time when no other program has asked for disk io for a defined
   grace period. The impact of idle io processes on normal system
   activity should be zero.[...]

   Best effort. This is the default scheduling class for any process
   that hasn't asked for a specific io priority. Programs inherit the
   CPU nice setting for io priorities. [...]

http://friedcpu.wordpress.com/2007/07/17/why-arent-you-using-ionice-yet/