The .243 Win is neither my FAVORITE range or deer cartridge, but does well at either. Barrels warm fairly quickly and barrels tend to wear out fairly quickly for a target cartridge. As a deer round, it's okay for fairly open shots, especially under 300 yards, but I prefer the .270 or .30-06 for deer hunting in Maine.
If you reload, it can be pretty good for range shooting by loading mild loads. IMR 4895 has been my favorite for light loads, since it is more flexible than many other powders, especially many ball powders. I haven't loaded target loads for that cartridge, since it's my heavy varmint/grandkids deer round.
For deer, I load 80 grain Hornady GMX solid gilding metal bullets and they work well. The sub-teen and teen grandkids use them and if I want to walk down back with my T3 Lite, I'll carry it occasionally, usually for coyotes, but we don't get long shots at deer on this property, so it should work fine for that as well. The big failing is that it probably won't penetrate an 8"+/- tree that a deer happens to walk behind close-by.
My .270 Win easily handles the up-to 450 yard-long shots on our favorite trail. Incidentally, I load some mild, .270 Win, 90 Gr. Sierra HPs for target shooting (turkey shoots) and they shoot very well and at the same POI at 100 yards as deer loads.
Good luck with whatever you choose.