To date, my favorite DC-DC switcher has been the very prevalent Linear Technology LTC3780 - High Efficiency, Synchronous, 4-Switch Buck-Boost Controller. It can be found in the [[WD2002SJ_LTC3780_Synchronous_Buck_Boost_Converter_Ebay_Automatic_lifting_pressure|amazon (and ebay) wild] for cheap as chips.
This no frills part operated comfortably in the 4 to 36V range and had no current limiting or Undervoltage Lockout (UVLO). For new designed, Linear recommend the LTC3789 but I've found a new favorite instead.
The LT8390 has a wider operating voltage range - 4 to 60V. I've always wanted to be able to support 48V systems.
In addition to the wider operating range, it also has an accurate Undervoltage Lockout with hysteresis, perfect for battery systems and output current limiting. Another plus is the Spread Spectrum Frequency Modulation for Low EMI.