In my experience Goodman units simply have more problems. Here is my idea of why.
If you go to your local Walmart you will see a computer for 249 bucks. WOW you say and the guy will tell you they use the same parts as every other manufacturer of computers. So is the public being ripped off by the other companies? NO.
Part manufacters (such as Copeland) have strict QC checks. The quality is checked many times as the parts are manufactured and inevitably some parts fail. They will still sell the operating parts for much less than the parts that pass the QC checks. That way companies such as E-Machine (and Goodman) can afford to make cheap models.
These things run at a certain risk going back to the computer analogy I have an e-machine that has been running without problems for 8 years but my friend bought one and has had problems with it since it came out of the box. There is no real parts warranty because the manufacturer of the parts dont give warranty on the stuff they sell that fail QC tests.
It's a crap shoot. You may buy a Goodman unit and never have any real problems but then again you may get one that never works right. It's a chance you take because in the HVAC department you literally get what you pay for.