I've had a couple of the 6.5/284's. Currently bought the Savage long range hunter. I don't know if this caliber is any more accurate than my 260's or 6.5x55's but it shoots the 130 gr accubond a couple of hundred fps faster. I bought it for long range shooting, and yet have not experimented with it much beyond 110 yds. As odd a caliber as it is, I do think that it is making its way into more standard rifle manufacturers inventory. I wouldnt be surprised to see a Remington or Winchester offer it or the 6.5-06. As far as 25 WSSM, I think its R.I.P.
BTW, I paid about $750.00 for the rifle at Cabelas