Depends on whether you like the self reflection which Adachi and Shimamura make heavy use of.
If yes, reading the LN will be very rewarding, since a lot of this cannot be translated well into a manga without adding a lot of text.
Regardless of the above, if you're 50/50, go with the novel and then read the manga, I like the experience to map what I've once read to images, blurring the line between them.