Reviews on Amazon.com tells the following :
One reviewer rated it low because color goes on and off only needs to get a newer tv or get an rf modulator to fix the problem
Others complained of the subtitle problem. Follow the advice of one reviewer here and choose a language other than English from the sub-title menu and they will disappear for good
I had the same problem when I first got mine(no picture via s-video). I soon discovered that this was because the player was originally configured at the factory for composite video and TV left/right audio. So, here's what you do: connect the dvd player into the back of your TV's composite video & left/right jacks. You should now be able to confirm a picture (DVD Player's initial screen). Next, access the player's menu, configure it for s-video and whatever audio system you are using. Finally, re-hook to your video audio system, and you're all set! I know, this isn't exactly the simple plug-n-play we are all accustomed to with higher end name brand players like my Toshiba, and the manual isn't going to win any literary awards in the near future. However, if you can get by this minor inconvience then you will find that the 550's benefits will easily outweigh its faults.
Another thing is to remember that the MacroVision protection might be extremely which could cause malfunctions with your PAL -> NTSC conversion. There are MacroVision removers for that (simple SCART schematic considering a Philips IC and some capacitors). Usually dvd players are exceptionally good converting NTSC movies to PAL output , but i've never seen the opposite way (which you need).