imacsae,
A good reason? You have too much cash in your wallet and need to dispense with it quickly?

You are correct, in most cases it's simply a drain and fill, which, unless there is a problem should be all that is necessary. With modern engines that don't have all cast iron parts, I wouldn't run one of the "cleaner", "conditioner" or whatever else they call it in there. If you really want to do make sure you get most of the old coolant out, drain, fill with distilled water, make sure your heater is set to hot to flush out the heater core, drain that after running up to temp and then fill with a 50/50 mix.

Some tout the use of a flush, putting a "T" in the coolant hoses. If you're changing the coolant out every two years, there should be no need for a flush.

Bogatyr