A few comments:
I tried the .204 when it first appeared, and it shot noticeably flatter and drifted less in the wind than the .223 out to "normal" ranges with the same bullet weights, say 400-500 yards. In several rifles it also shot more accurately than the .223, on average, perhaps because of the quality of early factory ammo, but perhaps not.
I soon ended up with several thousand rounds of .204 brass, but then the Obama Shortage hit, and .204 brass was one of the casualties. That's when the .204 Practical started to become more popular, because .223 brass was still available. If you were a handloader (and most avid varmint shooters are) the .20 Practical made more sense. If I had started down the .20 road at that time, it would have made more sense. But general .223 brass isn't as high quality as the .204 brass I have on hand. If somebody actually likes (or has the time) to sort .223 brass for consistency, or turn the necks, or whatever, then the .20 Practical will do the same things.
But the Obama Panic is over, though some other shooter panic will no doubt occur in the next few years. They have been, regularly, since the 1990's. But I don't really care, because of my thousands of rounds of high-quality .204 brass, and from from what I see on the Internet, there's plenty of .204 brass available now.
