Nothing like a hornet's nest on the "Night before Christmas" but good question! So to answer, yes and no.

Yes - the 243 is a good deer gun for the few that can:
1.) Shoot well
2.) Pick their spot and hit it
3.) Understand it's limitations and control themselves when things aren't perfect, angle, movement, range... etc
4.) for smaller deer

and then..

No - in my humble opinion, it is not an ample cartridge for shoulder shooting deer even with a "heavier" partition bullets.

So, I know thousands of deer have been killed by this caliber and it's cousin, the 6mm rem, but I have also helped track down too many deer - most outside my hunting party but to be honest, a couple within, to make either what I would consider "a good deer gun".

From my perspective their are a lot better choices out their and although I've seen them take deer with one shot I have also seen too many hunt with these and break one of the aforementioned rules... resulting in a long tracking session, lost deer.. etc.

I am no fan of either cartridge because, push come to shove, I believe in using enough gun and that measurement should be made based upon the worst possible shooting circumstances. That "not just quite right" shot on a buck of a lifetime comes and few can resist with catostrophic results.

I see your in TN - and although I have never hunted there I see bigger and bigger bucks being taken in all the southern states each year. Hate to have you loose one of those TN boomers betting on a 243. They can drop them like a bag of rocks on one deer and the next will run for miles. This can happen with any caliber but I'd bet on a 30 before anything. Your circumstances might be different.