Five axis if you calibrate it properly!
But before you jump into purchasing a wieghted stabiliser, do read this posts on
calibration http://www.clubsnap.com/forums/showthread.php?t=1466999
Find out more about the physics of weighted stabilisation here: http://entertainment.howstuffworks.com/steadicam1.htm
Personally, if you have using only one camera and your shots are unrehearsed, I will stay away from gimballed stabilisers.
A poorly calibrated rotating gimbal stabiliser is worse than handheld.
For cameramen starting out on stabilisers, I recommend trying out non-gimballed stablisers first. This will give you direct tactile feel of controlling moments and isolating axis of rotation since the rotating forces are transmitted directly to your bare hands.
Problem is, if you spend money to purchase something like a steadytracker http://www.steadytracker.net/steadytracker-ultralite/ you'd soon realise that the parts are so simple, why didn't you make one yourself? So may be you should investigate DIY as a first option.