Sounds like you are a little late in reviewing units if you already have a contrat to put one in.
One thing to note - "builder's grade", as noted in prior comment, does not necessarily mean what reputable builders and contractor's put in - it means what mass production builders can buy cheapest in quantity, so is normally equivalent (maybe) to what you find in a Home Depot or Lowes at the lower end of their lines. Many reputable contractors would not be caught voluntarily putting in a "builder's grade" HVAC unit.
You can google for reviews by Consumer Reports and other on A/C's - but generally, the comments you find do not indicate satisfaction or long life out of Goodman's. Goodman as a compnay has changed hands every 3-5 years over the past couple of decades, in and out of several private equity holdings groups that flipped it with new public IPO's each time, last time I heard was sold to some Japanese outfit. I know I have put it on a do-not-buy status as far as I am concerned, jsut based on comments I have heard from builders and homeowners. I hve heard of a couple installed in my area that were torn out and replaced with another brand within weeks because neither the contractor nor the local Goodman rep could get them to work reliably.
