About a year ago I bought my daughter a Sony HX1, compared the results with shots of my A550 (& Tamron 18-250mm), via a HD TV screen. To my disappointment, and my daughters delight, the HX1 won hands down: IQ in regards to sharpness, contrast and color was identical, however the HX1 pictures had less artifacts. Close-ups were better with the HX1.
Mind you, the tests done was nothing which would compare to DP standards, but reflected only the practical application of the cams in the field.
Have recently upgraded to the A55, since I have already 4 lenses. Otherwise I would have no concerns travelling light with a super-zoom compact P&S, of the HX1 quality. Too bad that Sony seems to have given up building it, without replacement.
Ideally, I think, one should use both concepts. With my heavy bag I lost many good shots, because I do not feel always bringing it along - and many good opportunities get lost.
Chimere