Liner offers more flexibility (no pun intended!) regarding shape and design.
It's also not "permanent", meaning that if you decide next year to change
the pond, you can do it without breaking your back (don't tell me that this
is your "last" pond - I won't believe you G). Also, depending on where you
live in the world, frost heave is not a problem with a liner, whereas it
could be fatal to a concrete pond. Many folks have concrete ponds and are
absolutely *delighted* with them, but more folks have liner ponds, I think.
Further, if the concrete truck starts making visits to your house, the local
inspectors/building code enforcers may take an interest in you . . .

Lee

"Garry M. Silvey" wrote in message
...
I've ruled out preformed liners and am now looking at Cement VS Flexible
liner. Any suggestions? I have lots of cement working experience, so that
is
not an issue. I am looking at building a 2 pond with creek in middle
system,
a small pond above a larger pond. Larger pond will probably be 8 X 10 or
12.