Hi Brett,
the NM are missing some of the bells and whistles that the NP have (later ones have traction control / stability control) but are otherwise pretty similar. I have a manual NP 2005 with the same motor. Gear boxes are pretty good, the dual mass flywheel can give up the ghost - mostly seems to be around 170 thou km, but I don't think there is a pattern. There are single mass flywheel conversion kits available. The rear drive shaft issue mentioned is the rear companion shafts - they sometimes 'pop out', loosing the diff oil. There is a hot fix for it, but it wasn't a recall. The fix costs around $600, and apparently can be done yourself if you are capable with the tools.
Basically they are pretty solid reliable vehicles, make a great tourer, and are good for everyday use (ours is the daily driver). They are good on fuel and handle well on road. Off road they are competent, they don't have the wheel articulation of the rigid axle cruisers or patrols, but its not really an issue unless you are into serious rock hopping.
We've done the Simpson (no trailer) and about 15 thou km with the trailer. I have no plans or desire to get another vehicle at the moment.
As Estelle said, get on the pajero forum, lots of info.
Richard