I'm not certain why boxer shorts aren't more popular among women. I would guess that the main reason is that they're simply not available for women, per se, and that they're definitely seen as masculine. I mean, if panties were the most comfortable thing around, you wouldn't see a lot of guys in them. That aside, I think that boxers are phenomenally more comfortable for everyday use than anything else available for guys, and it seems like women would find them comfortable too. I've known a couple girls who swore by them, but they were certainly a rarity.
But, eh, people are picky about these things. There are plenty of men who find briefs comfortable, which I don't really understand anymore. I thought they were comfortable up until I was about twelve or so and proportions corrected themselves, and for the latter half of my life I've found them pretty detestable. I guess there's a minority of guys who find women's underwear comfortable as well, even putting the obvious eroticism and fantasy elements aside. I don't get that. They look so uncomfortable. I mean, the higher-quality materials thing is nice, but... panties look like some kind of crotch-bra. I don't know anyone of any gender who thinks that a bra is the pinnacle of comfort, and my nipples are far less sensitive than other parts of my body.
I also don't get the commando thing. I've tried it, and going without is just horribly unpleasant with anything other than, say, gym shorts. It seems like it wouldn't be much more comfortable for a woman.
I tend to notice what underwear people are wearing. At some point you're bound to find out this crucial information about just about everyone you hang out with, as I see it. It's just yet another data point as you try to figure someone out. An interesting little nugget of uselessness.
So, I'm a boxers guy. Don't be shy; announce your preference to the world right from my comments page! Bonus points to any female who explains why they never tried boxers, or if they did, what they thought.