First off, the design of the trackpad may have been influenced by Apple since there is only one button. Whilst this is a non-issue for me since I am used to it, it may be an issue with others (I know a couple of peoplehate having only one trackpad button). What makes me dislike it is how stiff it is. It is quite difficult to click making it uncomfortable to use specially when moving windows or cutting and pasting. I don't know how to fix this so I am stuck with use it.
The trackpad itself is a joy to use specially when you set the sensitivity high enough. The vertical scroll bar makes web browsing easier. However, I miss the two-finger tap that's available on my Macbook Pro. :)
Personally, I try to avoid using the trackpad as much as possible. It is a good thing that the Eee PC supports USB mice. So go grab the smallest and most comfortable mouse you can find now!