Hi WhoDatRazor. You should be fine with the Pioneer BDR-209DBK. The only real difference between the two is the BDR-2209 also supports the triple layer (75GB) and quad layer (100GB) disks, which are REAL expensive anyway.
I too had tried an ASUS drive and immediately returned it, before I bought my Pioneer Burner. Believe me, you will be VERY HAPPY with your Pioneer.
As for scanning discs, It is really only useful for telling the 'true' quality of the burns. When I buy a batch of discs, especially new or different brand discs, I like to run some test burns at 4x, 6x, 8x, etc and then scan the quality to see which speed is giving me the 'best' quality burn. You would think the lower the speed, the better the burn, but that is not necessarily true always.
I know, I am kind of a geek as far as the quality scanning is concerned. Most people are just happy if they burn successfully. They watch them (movies that is) and if they don't skip, hang, or stutter, they are happy.
I really find the scanning useful for telling which brands of discs truly work the best with my burner.
EVERY disc (CD, DVD, or Blu-Ray) has errors when they are burned. The error correction algorithms in the hardware minimize the effects of these errors. But if the errors are bad enough, it is one of the reasons that you get the skipping, hanging, stuttering, etc. when you try to play them.
But, is it worth the investment of another burner just for scanning.....well that is for you to decide.
As for your ASUS burner, you may find that it will work ok on a Windows 7 machine, or with some other brands of discs. Another thing you could try is to check the SATA controller driver being used on your machine. It could be using some generic/Microsoft driver. Your Motherboard manufacturer may have a custom driver made just for their motherboard/SATA Controller that works better. Or you may find that ASUS will release another firmware upgrade at some point which corrects the problem.
I feel sorry for you finding out the hard way that they are problematic burners. I know that wasting/failing double layer Blu-Rays burns can get expensive at $3-$5 a disc. You can always try contacting ASUS and explain to them that you are tired of trying to get them to work and would just like a refund. Many times, even if the place you bought them from won't give you a refund, the manufacturer may. Especially if they are still under the manufacturers warranty period.
Glad to try and help....