My rule for buying new guns is, "will it meet a need not already met by something else I already have?"
Of course, I liberally interpet said rules, after all, I can always justify another Colt 10mm as it will give me a brace of them
The .22's I have, both rim and centerfire, are neat guns - the #1 in .22-250 is a dream that shoots as good as it looks. My Browning Lo-wall .22 Hornet is nice, but I would like to find a bolt action mid-size .22. Call it a no excuses rifle that can be shot a lot, without frying the barrel or breaking the budget. When I shoot..."no excuses"...if I miss, I know it's me, not the gun or ammo.
I think the right calibers for this would be a Fireball or a .223, partly because the ammo and rifles are readily avalable, and reasonably priced. They are considerably different in function than anything else I own, so it's a fair addition to the collection.
This new Ruger might be a fast stepper, but unless Ruger puts a
really smooth bore on it, it's going to foul like crazy. Long barrel life is good, but having to clean the bore every 20 shots ain't much fun.
Will the .204 reach out further than my .22-250? Well, maybe I guess, but I expect a 50 grain bullet launching at 3800 fps is going to be awfully close to the same results at 400 yards. I can load the same 50 grain bullet in the fireball, or in the .223, or in a Swift, for that matter.
So all that said, if I didn't already have a .22-250, or a Swift, I might consider this .204 as my long range varmiteer. Since I (and a lot of other folks) already own something close to it in performance, I can't see any reason to add this caliber. Mind you, if six months from now I stumble on a slightly used, .204 Ruger in a 40xb with a Exhibition Turkish walnut stock, at a reasonable price, I will probably flex my rules and strongly desire a .204