Like others have said, all that low-rpm torque and HP is what makes the 3.5L V6 EcoBoost such a great tow engine.
That link BenK posted shows the EcoBoost 3.5L with 420 ft-lbs at 2500rpm and the Chevy 5.3L with 383 ft-lbs at 4100rpm. Quite a difference in rpms.
I dunno how Ford got the peak torque down so low with the 3.5L (think all the smaller Ecoboosts have peak torque at 3000 or higher rpms). But it does make the engine more diesel-like in behaviour.
Still, if you like higher-revving V8's then Chevy's 5.3L should also be fine.
And the 3.5L EcoBoost has been available in different forms since ... 2010?
So it's been around for a while. Not exactly new. It's been pulling my 8100# trailer with ease for 22K miles so far.