I had a bad experience with Gildeprint. Summary: They made many mistakes, didn't acknowledge their mistakes, and did not respond to many emails. - The colours in the final delivery's cover differed from the test order. The colours of the test print were the correct colours, so this is very unfortunate. - I had given careful instructions about the crop locations of the cover and the crop locations were marked on the pdf file as requested. However, they edited the file and chose different crop locations without telling me. This caused the text on the spine to be off-centre. My emails asking why they had changed this were left unanswered. I had to correct this the old-fashioned way with a test print and ruler. - Gildeprint has a booklet with information about printing theses which is very outdated. The options I chose were not available anymore. So I just had to go with their choices instead of making informed choices myself. - Gildeprint caused several delays. Because of a deadline, this made it impossible for me to switch to another printer, which I would have certainly done otherwise.
