thirteen,
I own 3 flow staffs (4 if you count the old, old street lights they usde to sell) and love all of them.
On the question of weight, with 3 lights and 2 flow masses on each end, it definitely is weighty enough. This is even heavier than some of the fire contact staves I make, but lighter than most. It's comparable to the weight of a solid wood staff.
The only issues I have are that the collapsible ones do flex quite a bit. I've made a dragon staff out of them, and the bend like no other. So don't try doing staff yoga with it.
The silicon grip doesn't stay sticky very long, nor is it soft. You might want to add extra padded grip for comfort if it concerns you.
The collapsible staves only grip the center, and if your handle is short, or you do conjurer's staff, you might want to grip the ends too.
I bought silicon grip from flowtoys and gripped the ends of the collapsible for more coverage.
One cool trick to keeping your flowtoy staff grippier. They recommend using hairspray to put the grip on. I accidentally got it everywhere, but then noticed skin and clothes didn't shed on to the staff. If you spray your staff grip (almost any contact grip) and your clothes/skin, the grip stays grippier for longer. This is also a good way to clean your grip as it then makes it tacky for a bit. After about 5 coats you may have to wash it off depending on how you applied it.
As for glow staves, flow toys are the best for the price. Period.
If you have other toys/mods for the flowlight system. Then half the price is gone.
The flow well, the look phenomenal, they can take quite a bit of abuse.
The are very easy to personalize, in case someone just grabs it during a rave, you can quickly identify them and even beat them with it. Blood comes right off the strong poly-carbonate tubing. Kidding, but they are strong an clean easily when at flow camps.
if you are still worried about weight, you can always add more, but after a certain point, you'll have to grab a one piece flow staff.
Also, Concentrate's LED staves only get to about 4.6 feet in length, although the are slightly stronger and lit the whole length, the are about $300.
Hope that helps!
I found an old picture of what my collection looked like right before adding new grip: