As a former ecoboost f150 owner, I can say that when the truck was new and everything was working good, that truck was fun to drive and got decent MPG. After several trips to the dealer service center, a couple ECM reflashes, new spark plugs every 20k (kept cracking and sometimes blowing the ceramic right off), new coil packs, new intercooler, the decent MPG was gone and the snappy throttle response was also gone. By 45k miles the f150 had developed a nasty bottom end knock and a couple electrical glitches and that's when I threw in the towel. I just couldn't depend on the truck any longer and ford was dragging their feet to fix anything on it.
I've also had the opportunity to drive a couple 5.4L f150s for work but I wouldn't call them bulletproof. We had spark plug issues, coil pack problems, MAF issues, and finally cam phaser issues, not to mention they were absolutely gutless, worse than the 4.0 in the 5th gen.