I could agree with you on gdb's user interface. However, working on embedded hardware, plain gdb and it's architecture-specific forks|variants have been the least fiddly things to use.

The most recent examples I've stumbled upon were System Workbench for STM32 and Atollic Studio debugging relatively recent STM32F7 series. When the debugging from IDE doesn't work, it's very hard to see where the problem is (is the hardware interface service started? with the correct parameters? does it have access to hardware USB device? did it even succeed flashing the firmware?)