Re: 6.5x284 - How good?
My opinion, no more no less. The 6.5 cal is a terrific caliber. Great bc's, and high sectional density. With a dedicated hunting bullet, I would consider it a good 400ish yrd elk rifle. Use a bullet like the 130 Accubond or the 130 Scirocco. Shoot deer and antelope as far as you are comfortable or about 800yrds. That is where you will drop below the 1800fps mark.
To hunt... or not to hunt...? What a stupid question.