Xf1 and x10

Hello

I have heard some talk that the xf1 is not optically as good as the x10 ?

i realise it has a slower lens on the tele end which isn't a deal breaker for me but is there any conclusive evidence that its correct that the lens is not on par with x10 ?   Has any body got both and have any conclusions please?

thanks finput leeinput lee