Translate works page-by-page in parallel, so a 200-page document usually finishes in about 6 minutes. Pricing is 5 credits flat for documents up to 100 pages, and 1 extra credit per additional 20 pages above that.
Layout is preserved — fonts, columns, table structure and page breaks all carry over. Inline images stay in place; only the text inside the PDF is replaced.
If the source PDF is a scan, run OCR first. Translate cannot translate text that isn't actually text yet.