I'm not sure. The only working units I have these days are 3 Panasonics and two Toshibas. I haven't used a Sony, Magnavox or JVC machine (they don't sell them in Canada as far as I know). I have some unfinalized discs from old (c 2003/4) Centrios recorders (which were sold through our equivalent of Radio Shack/Tandy at one time) which I have tried in the Toshiba and they work also (and yes, I am glad I didn't throw them away when the recorders failed...).
Thus far I haven't found an unfinalized disc that won't play in the Toshiba. Of course, I haven't tried all possible combinations as I don't have them.
One interesting thing I learned through playing with this machine is that I was not correct when saying in an earlier post that the disc has to be finalized in the Toshiba before it can be viewed/played (just going by the manual on that). The 430 can read unfinalized discs from other manufacturers AND play them. In addition, in fooling around with the thing a little more today, you can record a few titles on a disk in, say, a Panasonic, then put the disk in the Toshiba, record additional titles, then take it back to the Panasonic for additional recording or finalizing. It manages to maintain the Panasonic menu structure on all titles when you do that... which is quite a feat.
I must say, I had no idea the Toshiba would do this when I bought it. It was just a cheap workhorse recorder (on sale) that I planned to use for general recording. It's far more than that, I find. Good chance I'll be buying another one...
Others have commented on the Toshiba picture quality. I would agree that on the LP (4 hour) setting, it doesn't do as good a job as the Panasonic. However, it's far from unwatchable on a 32/40" screen. I suppose if you are watching on a true big screen, it wouldn't look very good. But the Panasonic 4 hr mode isn't great for that either. Add to that, the Toshiba 4 hour mode actually allows about 4:15-4:20 on one disk (depends on number of titles and starts/stops/pauses).
The only drawback I've found so far compared to the Panasonic series is that the Toshiba doesn't have a flex record mode. I use that alot on the Panasonics.
If you want me to check specific disks, PM me and you can send me test disk(s) for that purpose.