There's a lot of factors to think of.
PJ's have the new replaceable rubbers which are easier to switch over, and they are cheaper. The new formula Carbon Fibre springs also seem very good.
In my experience PJ have much more helpful staff who are always willing to give advice (on anything, not just bocking
)
The new poweriSer 2007 models have improved bindings and calf cuffs. Some people prefer cuffs, others don't like them. They also have tan hooves which do not mark gym floors - PJ hooves do. The springs are also fibreglass rather than Carbon Fibre. However, they are more expensive, and the staff aren't as helpful.
At the end of the day, it's all personal choice. There is no "best" brand, especially between 2 such similar models.
