I am personally not a great fan of Rachmaninoff myself. I find it likable, but compared to the music of say, Bach or Schubert, it seems a little empty and missing something honest and deep to me.
Interestingly, some of my most favorite pianists (Moravec, Barenboim, Arrau, Brendel, Schnabel) have never played Rachmaninoff in public, although each of them had an enormous repertoire. Rubinstein only recorded the second concerto and Paganini rhapsody, but played it very seldom, to my knowledge at least.
On the Liszt and empty virtuosity thing : Liszt is perhaps very uneven when it comes to quality of his music. I am pretty sure that you didnt mean pieces like his b minor sonata, 3 petrarch sonnets, or the finest of his etudes. Also, Liszt, like him or not, is a much greater innovator in music than Rachmaninoff, being the father of the symphonic poem, impressionism, or even atonal music.
Lastly, I would like to say that Rachmaninoff was a great composer and even greater pianist. I feel his pieces are "unfinished" and are to be finished by a top pianist, of his own quality, because his recordings of his own music suddenly elevate the music to a whole another quality level.
I also love some Lhevinne´s recordings of Rachmaninoff, Richter´s recordings of Etudes-Tableux, Horowitz´ second sonata, and Vondráček´s third concerto. When played by your typical everyday pianist like Lugansky, not so much.
Just my 2 cents though