Having re-enacted for several years a slouch hat is much preferred over a kepi. It offers more protection from the elements especially rain, and is more useful for carring food, water, fanning fires and swatting bugs.
In the incident that I related about Jenkins' Brigade and the Texas Brigade, The Texas Brigade had been a part of the Gettysburg Campaign, while Jenkins Brigade had spent the summer guarding Richmond while Lee's Army was off in Pennsylvania. Hence at Chattanooga Jenkins Brigade's uniforms were of much newer issue and therefore stood out in appearences compared to that of the Texans.
As a matter of course I had a great-grandfathers in both of those Brigades, so the story was of particular interest to me.