They are good engines.
My company has about 30 F150 with the 4.6 & 5.4 engines. They have an average of 220,000 miles on them. The basic engine is very good. Things that seem to break are Alternators, Idler pulleys get nosier & power steering pumps go bad.
Overall, very good. They are all still running strong. We have one F150 that has 335.000 miles on it & it just started burning oil recently,