Arduino Leonardo bugs and lack of removable microcontroller
The question is if Leonardo is still buggy 


Probably.


  and may cause any confusion to newbie Arduino programmers. 


Definitely.  The whole way the Leonardo works is very different to the likes of the Uno. Transitioning from one to the other, if you don't know what the differences really mean, can be confusing.


  Furthermore, Leonardo doesn't have removable chip, so how can one transfer the project into a separate processor and use Arduino to the other project?


You build your circuit on a PCB and you provide an ICSP header.  ICSP stands for In Circuit Serial Programming.  You then use a hardware programmer to install either the Leonardo bootloader, which can then be used to install sketches through USB, or install a sketch direct without the bootloader.

Or, if you're making thousands of them you send your code to Atmel and they burn it to the chip in the factory for you - at a price of course.