Why not just buy a 7 RUM?? I'm sure both are very compairable in stats, but I'm assuming easier and cheaper to buy factory ammo for the RUM (Only b/c it's a Remington factory round). The STW has been around for some time, even before the Ultra Mags were a twinkle in Remington's eyes. I suspect both will be here to stay for some time.
I don't own a STW, but I do own a 7 RUM and have been pleased with the results so far. Even being a stock gun, she's a good shooter (taking a deer out past 750 yards this year, plus several groundhogs at extreme distances) and a hard hitter. Confortable for me to shoot (Rem 700 LLS) and I'm only 5'6" and 150, if that
She's got a heck of a bark, and plenty of bite on the receiving end.
I'm getting around 3292 out of 168 grain Match Bullets. I know close to 3400 out of those 150gr Nosler BT's, using Retumbo. At 750 yards she still pumping out over 1000 ft-lbs of energy with the top load.