Dpreview rated the TZ25 higher for image quality than the TZ30:
Panasonic Lumix DMC-ZS15/TZ25 Review: Digital Photography Review
Cameralabs agreed about the better image quality:
Panasonic ZS15 / TZ25 vs ZS20 / TZ30 vs SX260 | Cameralabs
I haven't read a Trustedreviews camera review for a while as I found their previous cameras reviews poor but that was a few years ago so may have changed now.
i was looking for compactness as i carry it with my camcorder. plus i like the sound of 20x zoom.
im gonna order a hx20 unless someone has a reason for going for the tz30.