Translating a paper in full leaves you unable to recognise its terminology; reading the original means running into words you don't know. There is a third option: rest the pointer on a word and get the meaning that fits the sentence — in figures and scanned PDFs too.
Bob and Hover Translate are both Mac translation tools — the same job, a different approach. Hover Translate translates on hover, anywhere on your Mac, with nothing to select and nothing to capture; it gives the meaning that fits the context along with the whole sentence; and the words you look up go into review automatically. A point-by-point comparison.