if it says it has recovered the bad sectors, then the image should be fine. if it cant read a sector, it should ask you if you want to try again, fill the sector with zeros or cancel. always cancel, clean the disc and try again.
it it still doesnt work, try a furniture polish product (like
Mr Sheen, which is only available in Australia and the UK, but it has fixed any CD/DVD i throw at it) just be careful with it and do not get on on the outside and inside edge of the discs. ive noticed that it can make the discs slip while in some drive. its protective against water so you would have to wipe the edges down with something else
if it cannot read a sector, then the disc will not work at all, or will freeze at any point where that missing data is located. if you must, you can use DVDmulleter to do a CRC check on the data. it also detects if the steatlh portions where rippied properly