I've just got an NB200-13L and have to say it seems quite good. I can't compare it to the N140 as i've never used one but had a play with the NC10 and would say the keyboard is just as good, the specs are better (v slightly faster CPU, longer battery life) build quality on both is about the same. The Toshiba also seems to be cheaper (£250 v £280) and gets even cheaper if the cashback offer still works.
With regards to pine trail i'm not sure on whether an improved batery life is going to make any more practicle difference. The NB200 i have has a nine hour batter life so adding an extra 2 hours or so not going to make any real difference.