man, and I thought you were an expert Shoeb
lol.
As Daveml said, SVCD is better quality than VCD (everyone I think knows this *just look at bitrates and sizes and all of that), but VCDs can be very nice quality also. Many people I know can barely tell the difference from it to DVDs (lol, strange but true), however SVCDs are very close to DVDs.
Typically this is the scale on quality (compared to DVD):
DVD=100%, SVCD=93%, VCD=85%, VHS=78%, DivX=50-96%(as many people aren't very good at them *guess same applies to others).
Figures are a rough estimate (can be lower or higher) but basically how the naked eye percieves things (not talking about technical side of things).
Standalone DVD players are not all made to play these standards and many give jerky quality for either or both VCD/SVCD. So you must choose wisely (that's why elpresidente started a thread on DVD players that play these things).
At the moment PS2 machines can only play DVDs. PSX 1 VCDs with adaptor, but the price of the adaptor is about the same price of a standalone VCD/SVCD player ($40USD) in many places (UK/Asia) so not worth it if you ask me.