as you can see from this thread, F1Wild, the only thing you can be sure of is that we've got a lot of passionate members who all love their own device the best !
that's because everyone has different needs, so devices are not "one-size-fits-all" as we can see comparing your experience with the jetbook to kris'... it's a lucky thing there are many different ones !
i have the sony 700 and i love it. i've not had any trouble with dust on the screen, and i've never had a problem with glare either as some have. it's true the screen is a bit inferior to the 505 (etc.) screen but this is most noticeable when you compare them side by side ; the screen is still perfectly readable. i read in bed a lot (in fairly dim lighting) with no trouble ; in the daytime, particularly outside in sunlight, it's even better. at first i was annoyed about the addition of sidelights because i don't like lit screens (they tire my eyes) and adding the sidelights is part of the reason for the decreased contrast / clarity of the screen, but i have to admit that i've used them several times and when i do need them they are great. one warning, they do drain the batteries MUCH faster than reading without them, but if you plan to use the lights intensively, i recommend getting a psp (non usb) style charger which plugs into the wall ; it charges much faster than the usb connection and i believe you can even read while it's charging that way, which would solve that problem.
i think either sony will be a good choice for you ; they are both excellent devices. the 700's lights seem to be pretty important to you, so maybe the best solution is to buy a 700 from a store where you are sure you could return / exchange it, and try it out for a few days to see how you like it. it's very hard to make up your mind based on other people's experiences since they might not have the same needs as you, however, one of our members has made a really nice video review of the 700 which might at least give you an idea of the device. you can see it
here.