I am an enthusiastic user of both. Consider loading your own.
My .204R has a 11 twist 26" #4 barrel and shoots 40 Vmax's at just under 3700 with IMR8208 or CFE223, good for up to 400 & able to spot hits.
My .223 has a 9 twist 24" #4 barrel and shoots 53 Vmax's at about 3200 with IMR8208 or CFE223, range about same but not as easy to spot hits.
Pros & cons:
.204R - brass kind of scarce, should have 11 twist or faster to shoot 40 Vmax's or longer, 30 deg. shoulder reduces frequency of case trimming; .204 bullets have higher BC's than comparable weight .224 bullets. 4000 fps may be reached with 32 grain bullets (speedy). Nice flat trajectory with 32 & 40 grain loads, increases frequency of hits. Able to spot hits.
.223 - easy cheap brass, 9 twist does great with 53 Vmax's to 73 ELDM's. 20 or so degree shoulder requires more case trimming, greater variety of .224 bullets. Small powder charges. Long barrel life. Large selection of suitable powders.
If I had to shoot prairie dogs or rodents for a living it would be a .223 AI - cheap buckets of available brass, long barrel life, long brass life, more available small rifle primers, wide selection of bullets, small powder charges, huge variety of suitable powders & the sharp shoulder reduces case trimming frequency. A 9 twist provides adequate stability for most .224 bullets under 70 grains.
Most .223 rifles have 12 or faster twists that will stabilize the 53 Vmax or others of same length.
Should your interest grow, consider a used .223 or .204R and getting it re-barreled to .223 or .204R. Loading your own is a necessity for shooting hordes of destructive rodents. Favorite bullets .204 40 Vmax, .224 53 Vmax. Recover costs of re-load equipment with 800 or less rounds.