I didn't like the F-1. I A/Bed them witht he V6 while listening to a Pink Floyd CD, and they were only like 5% better for me. They were a tad clearer, and a little more open sounding, but lost a little in the bass department. I can't remember exactly, but I seem to recall thinking they were a tad on the bright side.
The reason I didn't like them was that they seemed like some sort of mutant V6, which I've already got a few complaints about. Even though they had slighty more open sound, the sound stage was still very closed in and chunky. Not even so much blobby, but chunky. "Each sound WILL be in one of three sections!"
Well, they almost had it for comfort... They re extremely light, and have large around the ear pads. However, in true sony style, (at least with the sony's I've tried thus far) the driver elclosure rested on my ear, which I really hate. To combat the small sound stage, I tried pushing them forward and down. I actually managed to make a significant improvement, but at the cost of pushing them so far that my ears stuck out the back betweent he pads and the drivers. As if they didn't feel like they would fall off if I moved my head to quickly before, now I wasn't sure I wanted to take my hands off them.
My two main impressions were: "This is like a V6 for the kind of people who like to spend tons of extra money lowering their car."
(Which I find quite silly, since your just throwing money at the wall, as far as I can tell.)
And, "Even though this equipment looks much better than the discman I tried the HD590s on, I like the 590s a lot better."