Hi Ira
I have tried the NSTC and PAL disc's in 3 DVD Players (one which though expensive was notoriously fussy about Region codes and Disc Quality, ie it refused to play some copied discs)
All DVD Players Played both DVD's without problem. Only one thing that I did notice (and it was a faint difference) the NTSC showed up at slightly lower Quality picture on large screen TV (it was a faint difference I had to swap discs several times and still not 100% sure)
I tried it on a portable DVD player no problems (and no percievable difference)
Also on 4 computers
1 Powerbook Mac A OK
2. Old PC Pentium 2 500 Mghz (?) win 98 A OK
3. Compaq 3 Ghtz Win XP Laptop A OK
4. New emachines Win XP Desktop A OK
Either disc works OK here
George