Initially I had about a 50% success rate, using Aone DVD+R 8X Dual Layer (RICOHJPND01). I'm too cheap to buy Verbatim, and since Verbs are more than twice the price of these discs even with 50% failed burns it works out cheaper in the long run. After flashing the firmware of the burner the success rate was 100%.
One thing to watch out for though; I've seen reports that if ImgBurn notices an error with the VTS sectors in your IFO files, it will fix them when it builds the image - without telling you. This means that the IFO/BUP files aon your disc will be slightly different to your original. While you could argue that fixing errors is good, it's bad if, for example, you want to re-seed a torrent and have deleted the original files. The files stored on the disc will have slightly different checksums so your torrent won't be 100%, and you won't be able to be a seed.
Of course if the person who originally authored the DVD did it correctly in the first place, this problem would not occur.