I found this a trifle indulgent, not very economically-written. Chunks of it consist of two people sitting down and discoursing philosophy, basically the author putting forth his views directly through his mouthpieces. In one chapter towards the end, Amory Blaine gets into a car with two men - this scene appears to serve no other purpose besides letting him expound on communism to them. Also, this does not have much of a plot, which is something I personally prefer; admittedly, this was a literary experiment and not a linear novel. In general, I'm not saying this is bad; only that it did not interest me much.
I would read this, though, for Fitzgerald's depiction of Princeton life - the breakfast clubs, midnight jaunts, arrogant students, the popularity race. Secondly, for his philosophical insights, which made me think (or try to). Then there are Blaine's romances with various girls, which is the liveliest portion of the book and gives us an idea of high society then. Lastly, for Amory Blaine himself - a memorable, striking character of self-absorption and constant self-analysis.