The Flair 49 PRO is entirely manual, meaning you have to pre-heat the brew chamber with boiling water. The Flair 58 has an internal electric heating element that keeps your group head at a precise temperature.
If you crave the tactile, "off-grid" feel of a fully manual lever, the 49 PRO is a beauty. But for pure espresso performance and convenience, a stepped-down Flair 58 is nearly impossible to beat.