RE: Is the 204 here to stay?
I would say so. It's seems to be a good little cartridge that actually filled a useful gap between the .224's and the .17's. The sales of new guns in .204 Ruger have been really good, and all of the area gun stores keep them in stock all the time. I don't own one and don't plan to get one. I'm a huge fan of the .22-250, and there isn't anything that the .204 can do that the old 22-250 can't. My next 22cal rifle, if not an AR clone in .223, will be a .22-250 Ackley Improved with a fast twist (1:9") barrel so I can shoot the heavy high BC bullets. But all the people I've ever talked to who own a .204 have nothing but good things to say about it, so it really comes down to personal preference and the willingness to try something different. Since I already know how to handload the .22-250 and squeeze the last bit of perfornance out of it, I see no need to switch.
Mike