I really hope that they've finally got all this ironed out.
Linux's problems with dirty memory pages have made it awful to use since forever. My old 1 GB Athlon64 laptop (now deceased) would often end up in minutes-long read/swap/flush storms when loading applications (laptop disk did not help here!). I had to use hacks to mlock X.org, critical libraries and Gnome daemons in order to maintain any kind of interactive response.
Try running Evolution and Eclipse in 1 GB RAM in 64-bit mode and using the 2.6.24 kernel if you don't believe me. :)
On that machine Windows XP64 used to run Eclipse so much nicer than 2.6.24.