Usually I do just fine on the mailed offers, being that I
don't generally need to eat at the fancy restaurants. My comp
dollars have been covering my meals and some internet usage
at the Business Center.
One time I asked for 1 comp to the rock group Heart instead
of the 2 for Trent that came in my package and my host agreed
to it. Got a great seat - 3rd row front and center!
So like Jean says, Ask (something reasonable) and you shall
(often) receive.
~Ed from PA~