Price:
My 2011 FX4 had the EcoBoost, FX4 luxury package, trailer controller, and rear step. Sticker price with destination was $43,650. My price after Ford incentives and dealer discounts was about $36,000.

2015 Lariat had similar leather interior, also had trailer controller and rear step, but additionally had GPS, BLIS (502A), moonroof, 20" 'chrome-like' wheels. Sticker with destination was $55,600. $12,000 more than my 2011 was. I believe the only current incentive in my area is $1,000 customer cash, plus the 'private' $500/$750 brochure/club cash that sometimes applies.

Looks:
"Everything is very familiar but slightly different". That would sum it up... Looks good, but not staggeringly different. I think non-F150 folks could walk right past it in a parking lot and not notice it is a new generation truck.

Interior is a bit more 'super duty' like... Maybe a little bit 'nicer', but really just more different. I like the instrument panel better, but the big square vents less...

Exterior, particularly headlights and grill are a wash. The old FX4's, especially with HID headlights, looked great, other combo's not as nice. New truck with certain grille/color combo's also look great, other combos not so much. The new non-tow side mirrors look goofy to me. From the side and rear, again, I'm not sure a "non enthusiast" would notice it is a brand new design...

Powertrain:
Engine/transmission, I'm a big fan of the 3.5 Ecoboost. 2015 seems to be a bit sharper with the stock tune than my 2011, and transmission shifting program also seems to be a bit better dialed in than my 2011 stock. The new 'sport' mode is nice... It takes away the lazy shifting and rush to sixth gear that you get in normal mode without adding the heavy compression braking that you get in tow/haul.

The truck definitely had more of a growl. I assume is the sound enhancement because it didn't sound at all like a V6 turbo, had much more of a V8 sound. Stupid, but I guess right on target for those that just can't deal with a truck that doesn't sound like a V8.

For me, the 3.5 EcoBoost is what makes the truck. For MY wants and needs, I wouldn't even consider the 5.0 v8 or 2.7 Eco. I want POWER, especially at altitude, and the 3.5 Eco with the right gearing provides huge gobs of it. Fuel economy isn't my priority and I could care less if the 3.5 burns a few hundred bucks a year more in fuel.

Ride:
Smooth, controlled, a bit more refined than mine (though it could just be the very highway oriented stock tires on the 2015 and that I forgot how mine drove with the original tires)

Coolest bits:
What I liked best about the 2015 vs. my truck...
Slow drop tailgate and remote tailgate release. Cool! Amazingly, they still have seemed to not integrate the tailgate lock with central locking?? Maybe it can be programmed, salesman had no idea. [update: evidently it can lock with central locking... wasn't locking on our test drive truck. Maybe you have to turn the option on through the convenience menu]

Boost gauge: Hurray! Ford now has a boost gauge in the dash... It's digital, very small, pretty much impossible to read any specific numbers (goes from 0-20 without any other markings), but hey, better than nothing. STILL only have transmission temp in the 'additional gauges' section, still only have the one cool off road screen. Not really taking advantage of the digital portion of the dash, though they did add a digital speed readout to the dash display.

Engine/transmission refinement: Again, I love my current ecoboost and transmission setup, but the newer one definitely has been 'refined' a bit. Likely nothing more than a good aftermarket tuner could do, but factory with warranty...

[updated] Fold flat floor... This one one of my favorite features in the 2011, and thought it was crazy that Ford then stuck a big subwoofer in the middle if you upgraded the stereo. No more, the subwoofer (if upgraded stereo) is behind the seat now.