I've played around with a few different ones. An Asus, a Lenova and a Dell mini--though I don't recall specific models as they were friends and family members.
I'd considered one, but after using them they don't fit my needs. Namely they all struggled with streaming video. Espn360 stuttered, no HD stuff would play etc. That was a killer for me as a big use of my work laptop is watching sports on ESPN360 and HD tv shows on Hulu, the network sites etc.
Though I have read a bit about some new models from Dell etc. that have more power and can do the HD stuff--but the impressions so far from early builds were mixed and they'll be $100-150 more I think from the stuff I've read. And then you're getting more into laptop price range. and might as well look for a deal on a 13 or 14 inch laptop.
But if you don't need the power, and just want to do light web surfing, e-mail etc. which Netbooks are meant for, all the ones I've used do that stuff equally well. Just a matter of finding the battery life/weight you need, trying them out and seeing which keyboard you like best etc.
These netbooks have an ION in them, meaning they should handle said video playback well. Oh, and I'd hardly call these netbooks considering the screen size and price. I'd actually just save a hundred and buy a laptop. You'd lose the portability but the specs would be much better than both these two.
If I had to choose, I'd probably get the 1201N because apparently the Mini 311's touchpad is blah. If you're using this for traveling and battery life is really a concern, than I guess the 311 is your answer.
You might want to evaluate what you want your netbook to be able to do. I don't think the netbooks with ION are worth buying considering the price just for HD playback on small screen, when you can save for a couple of more days and buy a laptop that could most likely do more than just that. I would suggest looking at the whole new Pine Trail netbooks that were just announced earlier this month. Designs are looking nice and battery life is a major improvement.
Iunno, that's just me.