I recently managed to find a box of old pulp novels, so I have finally gotten my hands of Doc Smith's Lensman books which famously inspired Julie Shwartz & John Broome's Silver Age revamp of Green Lantern. I had never read them before, despite the fact that I am a huge fan of the GL mythos, so I figured it might be fun to share my thoughts on them as a make my way through each chapter.
The most obvious difference between the two mythos is how much more militaristic the Lensmen are depicted that wasn't really present in the early Broome stories, but Johns & Tomasi played up in their post-Rebirth revamp.
Another major difference is how much more mysterious and enigmatic the Lensmen's otherwordly benefactors, the Arisians, are protrayed compared to how pedestrian the Guardians of the Universe have now become after decades of creators bringing them down to earth and stripping them of any of the unknowable mysterious nature they once had.
The grueling and brutal 5 year long process each potential Lensman undergoes to determine their worthiness is also interesting as opposed to the more magical and mythic selection of the Green Lanterns by their rings. However, each seem to be defined by their incorruptibility. That last angle sailed pretty quickly with the GL mythos once Sinestro showed up, but I really enjoyed how much time and effort each Lensman has to put into even being considered for the job. The Galactic Patrol selects one million 18 year boys from Earth, then slowly wittles them down to ten thousand to one hundred before earning their Lens, which, like the Lantern's ring, is a symbol of their incorruptibility.