I'm ready to put in a new heating and cooling system but I want to get the best. I hear lots of things from the dealers but not much from people who own these things. Any thoughts on best units? I can spend a little money to get the best but I don't want to just waste it.

As someone who was in the HVAC business for quite a few years I can tell you that without a doubt its not the equipment that you need to worry about its the install process.

Most manufacturers of Heating and Cooling equipment use motors, contols etc made by only a few companies. Of course some of these controls and such are just for their units, but still made by outside sources.
All furnace companies must claim their efficency rate based on Goverment standards, So you really do not have to be concerned about that. So what is left? The install.
I have seen some of the higher priced systems fail after a short while because the installer failed to proerly size the duct system for the house. Undersized the gas supply for the furnace. Wired the controls incorrectly so the fans or other accessories failed to work properly. With AC systems, failed to properly size the pipes. failed to properly evauate the lines from air, and a whole lot more. All of which causes blame on the equipment and not the installer.

When installing new stuff, you need to determine just how long you intend to stay in the home. You want your best pay back. Sort stay. Do not go with the top of the line equipment. Staying for a long time, them spend some more money and get a longer pay back.

But as far as equipment. They all have builders equipment and top of line stuff as well. Get a good installer and lots of referrals on them. Do not make a big thing out of the brand.