I've owned the S90, G11 and Samsung TL500. I think the IQ difference with those "high end" P&S options is more theoretical than practical. You certainly can set up shots that make that difference stand out, but in the real world I much prefer the versatility of something like the SX230, which I currently own and plan to keep. Trading off maybe 5% IQ for lots more zoom, better video and other features works for me.
That is probably true for me because I view this as a snapshot camera. if you are going to be more obsessive about results something like S95, that shoots RAW, certainly makes more sense.