sliding gantry or sliding Base ?

[JohnJ]

I am aware that the machine footprint will be almost double the length if i am not using a sliding gantry.

My question is, is the advantage in structural rigidity worth it , or are there arguments against it, except the larger machine footprint.
I am mostly interested in

Anybody has empiric experience comparing the two methods ?

If i go with sliding baseplate, i obviously will use longer rails on the X axis.

*edit*
Regarding the mounting question of the supported Rails,
i probably will just use 40x80 Profile where the rails are, and just mount the rails with t nuts, as the spacing of the TBR20 is 40mm.
Any arguments against that ?
I want to avoid machining that large adapter plates.

Thanks,

Regards,
Clemens