I had been having trouble with my Sony CD-RW drive recognizing TY CDRs so I called Sony Tech Support and one tech told that they've never had any issues with anything like that before, but another tech told me that Sony drives can get finicky with certain CDRs over time - whatever that means...
They also said I could try running Drive Check (a utility downloaded from Sony) to make sure that everything was functioning properly. I ran the test and I really can't tell what the results mean.

Each test was performed with CDRs from the same brand batch except where noted:

Test 1:
Taiyo Yuden Silver
Write: Passed
Read:Failed

Test 2:
Prodisc
Write: Failed
Read: N/A

Test 3:
Taiyo Yuden Fuji
Write: Failed
Read: N/A

Test 4:
Prodisc
Write: Passed
Read: Passed

Test 5:
Taiyo Yuden Silver
Write: Passed
Read: Passed

Test 6:
Taiyo Yuden Fuji
Write: Failed
Read: N/A

Test 7:
Taiyo Yuden Fuji (Different Batch)
Write: Passed
Read: Passed

Test 8:
Prodisc
Write: Passed
Read: Passed

Test 4:
Taiyo Yuden Silver
Write: Passed
Read: Passed

So what should I make of these results? That the drive isn't functioning properly? That some CDRs in the same batch aren't as good as others? That this application blows?

This application sounds pretty pathetic to me. Get a copy of Nero CD-DVD Speed and that will give you a much better perspective of the quality of your drive and media.

I have Nero CD-DVD Speed - what test would best determine the write functionality? I tried all the read tests - Disc Quality, DAE Quality, ScanDisc, etc. and the scores were excellent.

Totally different approach: Are you sure those Tayo Yuden are not fake?

TY get pirated because of their reputation, you know.

They're not fake because I have this problem with TYs from different batches and manufacturers. I just got off the phone with Sony tech support and based on my DriveCheck results (media errors) and the the other info I gave them, they said that it appears to be just an issue with the drive being fussy about recognizing certain discs (my drive has trouble recognizing certain Rhino/WEA discs also). They said if my drive was truly failing, then I would be getting unsuccessful burns and rips, which I haven't. So it's probably something I just have to live with.