SVCD is also encoded (standered svcd) at 480x480 ntsc (not sure for pal) and can have a variable bitrate (like dvd) just like dvd, but most standalone dvd players will not read above 3500kbps (on svcd that is) and just like the above post, svcd is mpeg 2
VCD is encoded (again standerd vcd) at 352x240 ntsc at 1150kbps which is what the saturn will read. don't know if you need a special authoring program to burn (don't have the card, so i've never tried cdr to see if it worked) them, but i would imagine that it would work
Though I don't have one to test, I believe the VCD card produces very good results. Full screen, full frame rate. Essentially as good as VCD can be without extras like advanced filtering algorithms (i.e. as good as vanilla Windows Media Player achieves).