I’ve just read Explosion In A Cathedral and thought it was tremendous. I’m not so sure that there is the same level of “show-off erudition” as in Borges’s short stories, which I found rather challenging and, to be honest, rather dull (that is probably more reflective of my intellectual level rather than a criticism of Borges!). Quite a few of Carpentier’s descriptions of life on the islands seemed to me Rabelaisian in style, they were so vivid and full of life. I certainly agree with you that his style is very dense – there are so many words on each page – the complete opposite to Rulfo.
Anyway I would very much recommend it as a great read.
I am now in a quandary as to whether to read The Lost Steps or read some more Mariana Enriquez as I really loved Things We Lost In The Fire.