It's just two different ways of listening to music. I think both are better headphones, from an enjoyability standpoint, than the bass-light HD800s and old-school Stax and AKG stuff, and, if I'm honest, I prefer them both to the Audeze and Hifiman headphones I've heard, too, neither of which really impress me; sure the Audezes have bottomless bass, and are the closest headphones to sounding like speakers, but you need to spend thousands on source components to make them sound right, and compared to either the 650 or T90, they're just boring-sounding to me. All of the hifiman products I've heard just sound plain wrong, even with high-grade source components, crazy tube amps, etc; I'll take the T90 or HD650 over an HE-5 any day.
Actually, now that I think about it, maybe it's just me, but all of the planar-magnetic phones I've heard have a slightly veiled sound accompanied by an awkward peak somewhere in the upper mids/lower treble that just sounds wrong to my ears.
A subscription to Tidal and a Fiio E18 make my LCD-2F shine.