Kindle Direct Publishing paperback option is (nearly) unusable, stick with Createspace for print on demand
UPDATE: Amazon got rid of Createspace altogether, so KDP print is your only option now. Sometimes it will flag things for issues, several times, but if you keep uploading it, the document might get approved (still buggy, as of 2019). Also, the cover generator rounds to the nearest 10th page I think, so it’s not as