When comparing the outdoor unit, there are better units that use less energy and some more enegry, for the same amount of cooling. These numbers are expressed as SEER. You take the cooling output in btu's and divide by the number of watts of power usage. The higher this number (SEER) the better the unit along with that the higher the price. When comparing what the contractor was selling you and what you were going to buy elsewhere you should also look if the units are equal in terms of SEER's and warranty.
The high SEER models work good only if you replace all components (A-Coil, expansion valve etc)
The labor price of $450.00 seems very high for half a days work.