Day and night comes to mind.
is it a common round the 257?
You are talking "apples & oranges." Of course the .257 Weatherby is a much more potent round... does that mean you should get one??? That all depends on your personality... if you just gotta have the best (and you also reload), then go get it... but if you can be satisifed with a nice caliber that is more than sufficient for your purposes, stick with the .243.