Keep in mind that ISF calibration usually involves diving into the service menus, where you can really hurt the unit if don't understand what you are tweaking. That process usually includes the use of some fairly sophisticated/expensive equipment. The combination is why there is a charge for the service.
Having said that, buying that expertise will not be as painful if you view it on the basis of "dollars per hour of fantastic PQ from a unit that has been maxed out".
The ISF calibration, and the ambient light / screen choice (an art in itself) / distance to screen), combine to render the use of someone else's settings to be of questionable value.
Given the desired end result of the best PQ for the buck, you might want to scour the web (AVS Forum and Projector Central are two prett good sites) to see what users have to say about the projectors, screen choices based on ambient light, ISF calibration, etc. It can only help.
I was on the fence between a PJ and a plasma and opted for the plasma in January (58" Panny) mostly because of bulbs (plasma doesn't have any), finding the "right" screen, flexibility and most importantly - the "pop" relative to colors, blacks and details. However, had I chosen the PJ, I would have done the ISF calibration.
Hmmm, re-reading this post, I hope you can find SOMETHING of use before it puts you to sleep.
