I got the 900HA last week - IT's AWESOME . I had the 701 before. The 900HA is the same form factor as 701, better keyboard, bigger screen, new Atom processor, much better battery life and 160Gb HDD.
Bought from have2have. One week to deliver, there service was great. Cost about R4,900.
I looked at the 904, but it is a substantially bigger form factor - too large for a netbook imho.