so i thought i'd expand a little more on why i'm going the NEX route, because i was dead set on a PEN before sony announced these (you can see the posts saying so in this thread!). having played with both, the NEX is the only model that really feels like a new class of device. i'll explain;
size: the E-PL1 is pretty small, sure, but the NEXes are actually pocket-sized (lens permitting). the ergonomics and stylings are really great, whereas the PENs look like old cameras - now, i like the way they look, but it doesn't really suit the purpose behind buying something like this as a DSLR alternative.
screen: if you're going to buy a quality camera without an EVF, i think the live view mode is going to be pretty important. the PEN's screens are all small and kind of low-res, but the NEXes have really beautiful, sharp, wide screens that can be tilted up or down for shooting above your head or from the hip. again, not a big feature for the DSLR market, but i think it's a big deal for anyone who's buying a mirrorless camera on the grounds of convenience.
price: the PENs are really expensive! considering how close they are to DSLRs in terms of the way they'll fit into your lifestyle, the price is unusually high for the tradeoffs. i'm getting the NEX-3 double lens kit (16mm pancake, 18-55mm zoom) for the same price as the cheapest PEN with a single pancake lens, and i'm not really sure where the corners have been cut. the NEXes even have bigger sensors, and most reviews seem to be saying they easily match their competitors in terms of speed etc.
i think if you're coming from a DSLR background, the PENs or lumix G series might feel more natural to you (though even then, you'd think you'd want to maximise the size advantage) with the interface etc, but from where i am the NEX cameras are far more appealing. they feel like they're designed for what they are, with little compromise, whereas the NX1/PEN/G1 etc just seem like below-average DSLRs.
anyway, those are just my impressions from using both in stores! i'm happy to be the guinea pig for how potentially infuriating the interface might turn out to be, and i'm sure at some point i'll want to upgrade to a full-on DSLR. once i do, though, i'd want the camera i already own to keep some advantages of its own, and i'm not really sure the PEN would have many.