Hardly anything has approached the sheer audacity of its scale in SF ever since, mostly because the pulp constraints dictated it to be of minimal length, so Clarke's concepts had to be concentrated in a novella! Granted, it has been expanded into a novel, and not just once (I have not read Gregory Benford's version as yet), but this singular chunk of wide-eyed adventure reads better, perhaps, in a novella form. Brevity is certainly a virtue. Your mind's imagination can expand upon the vista, if you so desire.
The IMAX-large narrative consists of escaping the closed, stagnated world of the last City, undertaking the quest for Universal meaning and the uncovering of stupendous artifacts, the conflict between urban and pastoral ways of life, and many hints of Something Larger than yourself or your world. Edmond Hamilton might've written it. Leigh Brackett might've written it (in less optimistic tones, perhaps). Clarke however did it at the beginning of his career, with grace and a surprisingly "non-stuffy" style. This novel could benefit from a more fluid style of writing and more polished prose, but it remains a splendid canvas on which your imagination can fly — short, of course, of some Dante, William Hope Hodgson's or Tolkien's world-building.
Critics note that the space opera is undergoing a modern renaissance as a genre. True, we have a veritable British Invasion of fine writers (Reynolds, Stross, Hamilton, Banks, Asher, to name a few) and we may safely say that Grand Adventure is alive and well (maybe it just feels different among the endless "door-stopper" trilogies in Chapters, you know). One good example is Alastair Reynolds' recent gritty and sweeping in scale Pushing Ice, where a planet gets abducted into an alien cosmological structure, which in turn is a part and a mechanism in an even bigger super-structure of it all. We live in fortunate times indeed, able to sample such cool new epics together with the older classics of space adventures (and even some rare pulp stuff).
I hesitate however to broadly apply the term "modern space opera". Many books remain "adventures" only, and may be all the better for it. Stanley Weinbaum’s sophisticated planetary romps were definite Golden Age space adventures, but to graduate to the “opera” status, one has to shift the focus from the characters and single ideas to the “concepts” and “principalities and powers”. Yes, it is essentially a scale shift, and not always for the better. My personal preference would be toward scaled-down but more wondrous stories… simply because it is much harder to do it properly on a larger scale (it tends to dull your sense of wonder). It’s hard to write poetically about civilizations perishing in a blink. On the other hand, it is perfectly possible to write a monumentally engrossing thriller (with some grandiose and smart ideas) happening on a single spaceship, or a submarine (Frank Herbert did that in Under Pressure).