Hi Charlie,
Yeah, there is much less whip in an Xtreme pole, lighter and more rigid than the SLX, but you do need to be a bit more careful in looking after them than with an SLX. Keep on top of maintenance and be careful how you shut open windows if you have to.
But they are great poles. Worth the extra money in my opinion.
Check out the pole specs on Gardiner website for weight differences between the SLX and Xtreme.
The SuperMax is heavier than the Xtreme.