Hugely ambitious works - but how many are good novels?

I'll hold off for now on judging the merits of Rana Dasgupta's much-praised debut novel, "Solo," as I've only read the first 25 pages or so, but first impression is: pretty impressive. His writing is fine, elegant, and original, without being too self-conscious. Solo falls within the realm, I think, of novels that, at least initially, are showcases for the writer's vast learning - in the tradition of Ulysses (how could any one mind encompass so much). Today, we see novelists like Powers, Vollman, Mitchell, and the late Foster Wallace working this vein: their books may not be great stories, their characters may not be credible, but their work is hugely impressive and, for certain readers, the apex of fiction. Not sure yet whether to place Dasgupta in this company, but you have to scratch your head and wonder: how does he know so much? How does a young writer (he appears to be in his 20s or so), apparently of Indian descent and, from the jacket notes, a bit of an itinerant (educated in England, I think) know enough to write a novel about a 100-year-old blind Bulgarian who sits in his room and ponders or recollects all the events of his long life? It's a history of the 20th century from the perspective of one, and it doesn't have the musty feel of serious research, either. At times the opening sections reminded me of Midnight's Children, also of The Tin Drum, monumental works that try with varying degrees of success to encompass through one character the history of a civilization. Hugely ambitious works - but are they good novels, or little showcases?