Ok, just to make a few points clear:
1) The longrod, not the beer belly. I'm sure the beer belly works very well (added stabilisation!).
2) Why I disliked the longrod:
I use the 'traditional' version of the XS-PRO, called the Carbone Pro, which is a longrod (same rod as on the XS), with a slidey v-bar and sidebars mounted on it. It's about as expensive as the XS but I got mine cheap
(check both out at
Arc Systeme : Products). The XS is a longrod which is attached parallel to the line of shot via a shortrod and offset bracket. The idea is that the rod can be placed either side of the riser and slid forward and backward to create the ideal balance. I believe that this is intended to be a compound stabiliser as side bars cannot be fitted to it, and recurve bows tend not to have a side balance problem to the extent that compounds do.
On a compound, using a longrod and a sidebar or offset bracket to balance the bow works because the weight is in about the same place as the weight which is being compensated. On the XS the weight is *all* on one side, meaning that while the bows static balance is as good as with any other stabiliser (nothing to shout about for the money) the bow has a tendency to pull outwards when shot. It's not so much that the stabiliser is terrible, just that it doesn't work as well as cheaper alternatives.