Well, Upstate, now you've gone and done it. I don't know what to tell you.
I shoot and have both, and like both.
(long pause)
The short answer is get the 243, it is the more versatile of the two.
The cost of 243 brass is almost twice that of the 223 cases, but you don't lose them in a bolt gun and are reusable a good number of times. Bullet cost about the same, maybe a bit more for quality 243 bullets.
223 is what I shoot the most of. 2 AR's and a bolt 223. I also reload.
Out to about 250 to 300 yards the 223 will preform well but the kinetic energy of the 223 will wain in comparison to the 243. If hunting is in your future with the rifle, then it is a slam dunk for the 243.
If all you want to do is paper punching, then the 223 will surfice.
Wind will effect the 223 (55 Grain) to a much greater entent than it will the 243 (95 or 105 grain bullets) and if you want you can push the 40 grain 243 to 4,000 feet per second (shorten barrel life however).
I have posted two pictures, the first is a Savage 223 the second my 243.
Tough choice, I like both.
Jim