how are the quality of these dvd-r

Never heard of them or any one using them. Do yourself a favor and buy a trial pack of them first. Just because they work for one person doesn't mean that they are going to work for everybody. Or you can just stick with the recommended brands of media or whatever has worked for you in the past.

Cheap & cheerful e-bay item $64 for 100 .... doesn't say what dye - probably Princo rubbish.

Dont bother m8 ... just get yourself some Riteks ... they'll cost you more, but they will work out cheaper in the long run and they are reliable.