Someone had made a comment about having a heavier inner core for their glow staff to make it better for contact, if you do a search you could find it... I think it was mcps glow staff that had it. (I also think it was a flowtoys glow staff)
I personally would choose the concentrate staff... I don't own either, but I have used the flowstaff doubles and the concentrate doubles and preferred the concentrate ones, they had a good weight and looked more effective to me for the patterny type movements (Because of the diffused light)
The flowstaves I found looked slightly better when you do lots of spinny motions, pirouettes and such... but again, with the concentrate staves they can look VERY effective with pirouettes on certain settings (like a segmented rainbow umbrella)
The main reason is that its easier to turn on... I have the flowtoys poi and it can be a pain to get the individual lights and turn them on, especially if my hands are cold (which they usually are if I'm using them... because they tend to get used at night) or if I'm intoxicated in any way.
I guess the final clincher (if I needed it) for me is that the guy who makes the concentrate gear is local to my area... (Lives in the same state as me)
But this is from someone who doesnt own either staff.
Oh... on breakdown... I THINK that if you wait flowtoys might have a breakdown flow staff in a way... Like this...
http://au.youtube.com/watch?v=ImfZ0KKQutw