So it appears HEF has it's advantages over the pure external i.e. a bit more comfort and maybe a little faster, less recovery time? Are the risks of permanent knee pain from LON not worth it over the external/HEF or do the advantages from LON outweigh it and is a better option in terms of pain and recovery (and also sleep since it's almost impossible to sleep well with the frames on - also have to sleep on the back and not all people can do that).

Why it concerns me because I heard the risks of knee pain from LON are really not that high as people think they are - it's just a misconception?
External frames, as a general consensus, are the most mentally as well as physically challenging method of LL a person can undergo.