I have a Sony DRU-510A and have burned many DVD's over the last year or more. I have always used 1x ACCU DVD-R's the entire time. I've rarely had a coaster and they are all working fine after 1 year. Just this last month I ordered the 4x ACCU DVD-R's. I ordered all of these from Meritline. One odd thing is when I select 4X it says they are burning at 4x but it just is 2x since it takes around 35 mins. What I don't like when I see them stacked in the spindle they seem more flimsy and not as flat as the 1x's. They just have a much cheaper flimsy feel and don't seem even. As well, since I have been burning these on quite a few I've had problems. I have had few coasters but when I play then on my Samsung DVD Player I get garbled pictures throughout some of the dvd's and have audio cut in and out and sometimes they simply stop playing. Sometimes it's the beginning of the dvd, sometimes the end. I don't know if this is all ACCU DVD-R's now or just the 4x. I am tempted to just try to order 1x again but as well, is there another brand I shoudl look at? I've heard a lot about BeAll as well as Ritek but I know there are many types of Ritek. As well, it seems that a lot depends on where you order from and when since sometimes it seems they change from one manufacturer to another. I'm interested in any suggestions of reliable media and I"m glad to go to 1x if that's what it takes. For now I'm burning any 4x accu's at 1x and am hoping that helps.