Polar M21/M32 or M51/M61 ? Is there much difference in the new models?

[T]

Hi

How much better are the Polar M61/M62 over the M51/M52 and M31/M32 over the M21/M22. The price
difference in Australia is about $80 and I am not sure it is worth it. Has anyone got any
comments please.

Cheers

Tony