I'd have to solidly disagree that a 243 will have the same terminal effect as a .270 with like bullets. It aint even close. The .243 wont even keep up with the .270s little brother the 25-06 as far as terminal performance.
Yep the .243 has a lot of fans but so does the .223 and both kill lots of deer every year. I have no qualms with those that use either but I'm a believer that a larger metplat even at lower velocity within reason provides better results.
Nothing might live with holes in vital organs but running off to die or un necessary trackin aint my goal...
For the young shooter that 8 or so lbs of felt recoil in the .243 may result in higher accuracy for shot placement than the 16 or so lbs of felt recoil in the .270.
Sure the .270 will deliver more energy on the target at each distance, but deer are thin skinned so .243 suits the job most excellent. One doesn't need a heavier or faster projectile on whitetail. Their anatomy structure and thin skin characteristic allow for easy penetration when the aim is true.