You get what you pay for.
compared to iphone 5/6: more power, bigger screen, fantastic build quality and aesthetic design, worse camera and OS
compared to galaxy s4: no competition... you'd have to be crazy to go for a galaxy after using a one plus, imo
perhaps s5 would be a better comparison, dunno tho
one plus is obviously selling these phones at a low price point in order to get their foot in the door. they already jacked the price up on the one plus two. the three will probably inch even closer to normal prices.
yeah, it's not necessarily the best phone, but if you think it's somehow out of place amongst the 'flagship' phones, you're either ignorant or kidding yourself.