These samples actually make the SP-590's low-ISO sensitivity shoots look better than they are, because the ISO 64 and ISO 100 crops are sharp and relatively free of artifacts. Even so, you can see how image quality starts to degrade at ISO 200, with both an increase in color noise and a loss of detail.
That yellow discoloration you see is the result of poor image processing in the blue channel of shadow areas combined with the texture of the statue. Though I couldn't reproduce it on photos of other subjects, it was definitely present in all the photos I took of this statue, and I've never seen it with other cameras. (1/100 sec, f5.6, ISO 100, AWB, 219mm equivalent)
As expected, at its maximum wide angle 26mm equivalent the SP-590 UZ produces some barrel distortion, but it seems relatively symmetrical (which is easier to fix in software than asymmetrical) and not unusually bad.
Like most megazooms, the SP-590 UZ produces its sharpest shots in Super Macro mode, and the results are pretty sharp. However, you can also see some of the color noise appearing on the gold contacts, even though this shot is at a relatively low sensitivity of ISO 125. Oddly, Olympus fixes its Super Macro at 51mm equivalent; most cameras fix it on the camera's shortest focal length. (1/80 sec, f3.5, ISO 125, 51mm equivalent)
Though this was also shot in Super Macro mode, it displays the more typical sharpness quality delivered by the SP-590 UZ. Photos look sharp at smaller scale, but everything looks soft when you scrutinize the photos close up or print at a full size of 16x12. (1/60 sec, f3.5, ISO 100, ESP metering, AWB, 51mm equivalent)