I'm with Bill, I see nothing about a Trane that makes it better than Rheem/Ruud. I prefer a Copeland scroll over a Mexican made recip that many 13 SEER Tranes use. Rheem is much more likely to use pressure protection. With compressor in the separate compartment, easier to work on or replace if necessary. We've got to change a big orange compressor today, will take 2 guys and 1 will have to GET IN the unit.
Is it true that keeping them shaded increase the performance?
It helps in the summer, but not as much as it used to help. The newer designs are not as sun sensitive. The coils on my system are shaded by louvers to increase efficiency and improve appearance. However, the new R410A systems do have issues with very high OD heat over 120*F according to some sources.