Spoken as a reader, I usually look at the map at begin of the reading, but mostly ignore it while reading. The map may be nice and artful, but for me it's the same as the cover. A good story I can enjoy without it.
In some novels the travels of the character are so confusing, that I need the map, to keep track. But mostly I think, the author should avoid this confusion.
At last I have an examples, where I thought the map was really useful and really part of the book. That are the Metro-novels by Dmitri Glukhovsky. The story plays years after a catastrophic war and the survivors are living underground in the Metro of Moscow. So the map contains the Metro-plan, but it is altered to show the new political zones, that have established after the war. It was really fun to follow the travels of the character through the map.
So my conclusion is: Include a map as an art-object but not as a necessity. If you feel, that your reader cannot follow the story without a map, you should try to simplify the locations. And if you really have a plan to make a map part of the read, then go ahead.