Virtually all A/C manufactures use the same compressor, the Copland Scroll (
http://www.emersonclimate.com/en-us...oll_compressors/Pages/scroll_compressors.aspx). It's the best there is for the 2 - 5 ton units. The air handler motor and the condenser motors are now all variable speed. Some are two speed but again, most manufactures buy off the shelf motors. One of the more common ones is called X13 for the air handler blower. Carrier uses their own specific motors and are very expensive (proprietary), $500-$700 to replace a fan motor. The only area that is usually manufactured specific is the electronics that control everything right down to the thermostats. The air handler box and outside unit usually are manufacture by themselves. The lower priced units (other than Trane and Carrier) out there may have off the shelf electronics and parts are ready available at suppliers, that is why many AC guys prefer these unit. Therefore, most A/C's are very similar with a lot of off common of shelf parts. How they use the electronics to control the units and with some intelligence plays on the SEER rating.
I googled Daikin and it looks like a European Company and starting up in Houston. (
http://www.daikin.com/press/2015/150107/index.html) You have to find out what parts are they using and as a new player in the market if they have proprietary parts. There would be a limited source of parts and other techs or service companies that may not be able to service the unit.
I live in South Florida and it's almost all A/C only and at my other home (a Carrier unit that came with the house) in Orlando, that area is almost all heat pumps. Be sure to get the AUX heater in the air handler with the heat pump. The common choice for most A/C tech is Rheem or Lenox since their parts are not all expensive and can get them at the suppliers.
If your heat load is that high you might want to invest in some energy saving techniques unless your square footage is very high. If it's single floor home you might want to add a second unit and split the duct system. If one unit fails the second one can at least provide cooing in part the home and save money buy keeping one section of the home warmer if not occupied much. A two story it be more difficult.
So what is a good unit, I see them almost all the same. I have two A/C unit's for my S Florida home that are 13 years old with the Scroll Compressor. The only problems have been the electronic parts buring up, but since they are an OEM (Tempstar) it was cheap fix.