James B, are you completely sold on the .243 caliber? If so, and it's what YOU want, by all means buy one.
Cheatermk3 gave you the best information there is, buy the one out of the 3 that YOU like the best and want (if your sold on a .243)...it's great to ask what others think though, I do it all the time myself.
Since you already have a .223. check out the thread right above this one about a youth rifle in either .243 or 7mm-08, I know yours is not a youth rifle but the comments regarding the caliber still hold true. My opinion and recommendation is to go for a caliber that will stabilize and shoot a bit heavier bullet, I think that is what you want and what will make you happy. In short, for a great versatile caliber go for one of the 7mm's, and the 7mm-08 Handi is easy to shoot (low recoil), accurate and light. I have a 7x57 Handi and it's a sweet deer gun. I also have a .280, but after reading your post and tying to see what you want, the 7mm-08 gets the nod, it shoots heavier bullets GREAT and fills the bill in every respect....<><.... :grin: