Day and Night is a brand manufactured by one of the big companies who produce equipment for private labels. I woudn't say anything bad about it. Trane would take issue that it is as good as theirs, but they just feel that way all the time!! Day and Night seems to have very good warranty coverage.
I would say the most important piece in the equation is the installing contractor. Get a good one, because no matter what the brand, he is the biggest factor in a good system, and in future warranty issues if they should come up.