I have owned the 243 and 25 WSSM. The 25 is the more versatile of the 2. Shoot 75 Vmaxes or up to 120 grain big game bullets. It is not quite the match of the 25-06, the latter being usually at least 24 inch barrels. But in my Featherweight , 22 inch barrel, 100's at 3150, 75's at 3600, and 120's at 2925 is plenty stout. Also the light trim guns are nice to carry. Can't beat the 25 WSSM in most situations in my book. I own and have shot for years the 25-06. Not biased on caliber, more on the weight and balance of the weapons.
The 25 is easy to load for, the brass is thick and tough and the ammo nees to be operating in the upper ranges of its intended pressure in order for the cases to seal properly.
Just my rambling, I'll stop now.
GregH