The best thesis binder really depends on what your university says you have to do, like the submission rules, how many copies, and if your work is going to be kept in an archive. A lot of institutions ask for a hardcover or library binding, but some also allow a softer cover option, you know, the usual more lightweight solution. Before you print anything, take a last look at the page margins, figure out the spine width, check the paper quality, and read through the cover wording just to prevent expensive reprints that’s the annoying part. Did your department give binding guidelines, or were you free to pick the format yourself?