I can only compare 243 Win and 25-06 because I've never own, shot or reloaded for the 257 Roberts.
243 Win
- short action (+)
- better target/varmint bullet choice (+ for varmint)
- better accuracy (+ for varmint)
- best varmint/deer combo
25-06
- long action (-)
- much better large game bullet choice (++ for deer)
- much more potent (+ for deer, around 100yards more in effective range)
- much better all-rounder (with a great bullet in will kill elk and moose)
If you're a shooter, varminter and once a year medium range deer hunter, definitively get a 243 Win.
If you hunt in the plains or in the moutains, the more potent 25-06 might be a better choice.
As for the 257 Roberts, get a 260 Rem or a 7mm-08 instead unless you're really into 25 caliber cartridges because of the limited choice of 0.257" bullets compared to 6.5mm and 7mm bullets.
Personally, my small rifle is a 243 Win and my big rifle is a 270 WSM.
Alex