I think Panasonic's numbers like "25" seem to refer to a budget version of another camera. In any case, while they look almost identical it seems the TS25 is quite different from the TS5, as you'd expect given the price.
The 5 has a CMOS sensor; the 25 a CCD. The 25 is 25-100mm, the 5 is 28-128mm. So optical zoom is different. Aperture is different. Different resolution viewfinders. More controls in the 5, better features. Find a spec sheet for both and take a look.
I have the TS5 and love it. I actually now use it a lot for macro stuff since it seems to do very well at that, which I guess you'd expect for a camera optimized for underwater use. The wifi is particularly good (none in the TS25 of course), and it does GPS itself. Sort of handy for geocoding since my mirrorless doesn't have GPS. Time lapse too.
Since the Canon (I assume he's referring to the D30) was mentioned, I should say I considered it. But frankly the others (Olympus, Sony and Nikon) were all stronger. The Canon doesn't have wifi, timelapse or some other features I wanted.