Strut bars are a good modification for the following people
1.)You have your vehicle lowered more than 1"
2.)You have sport springs or shocks
3.)have a tire profile of 45 or below
It is a good mod for those who have changed other suspension components that can effect the way the car handles.
Strut bars are not proven to provide any better lateral grip usually, but if your goal is to stiffen a frame that has has one of those 3 items done to cause more stress on it, then it may be worth your while. Stay away from bars with pivot points as pointed out above, they are virtually worthless, but cheap.
Bars to look at:
Neuspeed
Comptech Sport
Mugen
Sprint
Finally, adding those bars is a small piece in the puzzle, but, it is a piece.
Everything is working against keeping the tires glued to the ground. Strut braces if anything aid in keeping the tires planted or help them form being unglued in extreme cornering situations, or turbulent road conditions. Keeping the frame stiff, is the goal, a cheap way to do it is a strut bar, one w/o pivot points.
-www.hstuners.com