In most climates, the huge premium you pay for the ultimate equipment will have NO economic payback. There could be some advantages in comfort & humidity control, but don't look for those thousands back in energy savings usually. Putting that extra towards windows, window tint, insulation, duct sealing, all could pay back so much faster.
One thing to watch, depending upon size, you may be far from 19 SEER with these units. Check the specs carefully for the size you need.