To say you should get a .204 because the sd and bc are better than the .17 doesn`t win the arguement because the .22 has a better sd and bc than a .204 and they are cheaper and easier to find than the .204 componants. I have 3 different .17 cal rounds I load and shoot. My favorit is the .17 Ackley Hornet. I also have a .204 in a CZ that is my present carry gun most of the time. I also have 5 different .22 cal. rounds I load and shoot, 6 if you count rimfire.
I said all of that to say all of this. There really just isn`t that much difference in the preformance of all of the varment rounds I load. Yes I can show you On Paper, where 1 round has the advantage of another, But, most of the time in the field, most of the shots will be at a range that any will do the job. Yes this was said by a guy that is seriously considering a .22-284 so that I will be able to push an 80 gn. .22 cal bullet at 3,500 fps. for the best in long range small cal. accuracy.
When we start talking about the small advantage one has over another and really buying into that and spending our money on the newest and latest and greatest the gun is no longer a tool but a toy. And he who dies with the most toys wins!
Now for my oppenion. For PD`s and groundhogs the .17 Rem. will do anything the .204 wil do. For coyote I think that the .204 has a very slight edge. If you reload ammo availablity is of no consern, if not it is. Both are great rounds and you can`t go wrong.