I've had it installed on my L1020 (and the other phones mentioned) for over two weeks now. I haven't noticed/observed any drawbacks yet. Touch sensitivity wasn't affected. Screen readability has improved. Finger prints still adhere to the surface, though it takes a lot more oil this time - and it's easier to clean the screen now. I haven't (and have no intention) of testing scratch and impact resistance - but other more generous users have uploaded user reviews in the web demonstrating the resilience of the screen after applying this particular liquid screen protector... the glass won't become bullet proof, of course.
Theoretically, I suppose the only drawback (particular to the L1020) is that the silver-coated anti-bacterial screen will be covered by this material, so the screen won't be as "sterile" as intended. There is no mention about the anti-bacterial properties of the liquid screen protector.
Finding a good one will be tough since its screen isle isn't completely flat.
I got one for my old Lumia 1020 (now owned by my wife) and it kinda spills over a bit to where we can see mild imperfections even though they downsized it for the sake of dodging the screen curvature.
Thanks for your feedback. I had already done some research after you first recommendation (found a very interesting video by Linus Tech Tips) and ordered one from amazon which came yesterday which I've now applied. So I'll see how it goes. Thanks again.