and I might get flamed for this... but here's the skinny:
Mac OS X 10.1.3 is tolerable on it, but I am going to be switching to Mandrake Linux as soon as this semester is over. I am tired of the sluggishness of the system. The video cards in the Lombard are not supported with acceleration under OS X, and apple will never support them.. so you can't do anything 3D in os X at all. It has been amazing to use the linux underbelly of the gui (I'm a programmer, and have written a ton of code on this machine) but good old fashioned Linux is just so much faster....
So it really depends on what you want to do with the machine. If it's just for some word processing, email, making CD's, surfing the web etc, the Lombard is fine. You'll get the little spinning beach ball of death from time to time as you wait for the gui to catch up with you, but it's tolerable. If you were hoping to play any good games or you just need a really fast and responsive interface, then stick with 9 or delve into the wonderful and woolly world of Linux.
My next machine will be either a 14" iBook or a TiBook.. probably will buy it this fall - at which time I will probably come back to OS X, as it screams on the newer hardware.
-quangdog