I have very limited experience with improved rounds, owning exactly one - a 338-06. Practically speaking there would seem to be very little justification in improving an '06 based cartridge if increased velocity is your holy grail. On the other hand there would seem to be little reason not to improve. In my own situation I wanted a 338-06 & I wanted it on a model 70 classic action. This meant a new barrel & all the associated costs of rebarreling. The dies cost a bit more but that cost was only a drop in the bucket. One must be a handloader but that is hardly an impediment to all on this site. You must also fireform your brass but, again, that is no burden as most of us will (or should) practice with your new weapon. You are always left with the option of firing the parent cartridge should you lose your improved ammo.
In the end you are left with a cartridge with a touch more velocity potential or you can opt to run at standard velocities at lower pressure.
If you are of such a mind an improved cartridge is fun, very slightly more powerful &, above all, different. What's not to like?
