The Calcutta Chromosome was fun, and I don't at all regret buying the book. I enjoyed the twisty, wandering, plot and its labyrinthine internal connections. I enjoyed the scenery, both the futuristic New York and its wonderful evocation of Calcutta. I liked many of the characters and enjoyed their encounters and dilemmas. I enjoyed the bits of medical history. I enjoyed much of the language. I REALLY enjoyed reading a book where, for once, I did not have to wince at words misused or misspelled.
However, for all the blurb evocations, this is no Borges, nor Pynchon. I see why the comparisons were drawn, but there are some major plot and even ... call them philosophical... flaws that drag The Calcutta Chromosome back from a really good book to a fun read on the 'plane.
Basically, there is a vast and bizarre conspiracy, which, while entertaining, is founded on mushy, ill thought-out motives. There is an attempt to evoke an east/west - mysticism/logic thing, but it collapses under its own inconsistencies to reveal a balding plot device wearing a toupee of picturesque Oriental mystics.
Finally, there is quite a bit of pseudo-scientific and technological hand waving. This will bother some more than others. The point that technology can be like magic is relevant, and in places I can forgive the more nonsensical bits as contributing to a good story. There are other incidents, particularly the absurdly retrieved e-mail, which could have been tied into other themes in the story but weren't. Instead, I was left with the impression that Ghosh wrote himself into a bit of a corner and couldn't be bothered to take some more plausible method of getting himself out.
Sit back, fit together the edge pieces of the jigsaw puzzle, admire the pretty picture, and try not to be disappointed if you find a few of the middle pieces missing.