I have never used Shellac before but I have some, I might try it sometime. As for the lacquer over the oil I just decided to try it out and see what happened. I have no idea what will happen to the finish over time but it's just as good as it was when I sprayed it over a year ago.
I have never used tru-oil honestly and for a couple reasons, mainly because it's to expensive for my taste, I have seen pictures of it before and didn't see much difference in the way it made things look compared to other oil finishes, I have used both linseed and danish oils and I like the way they look better from what I have seen from tru-oil, and the luthier I go to for advice said it looks similar enough to linseed (which I agree with). Who knows I may change my mind if I ever use it but as for now I am not going to be using it anytime soon.
I mean this with all due respect and I'm not trying to fight at all I am just saying what it is to me at least and from my experience with other oil finishes.