For strut rods there is some benefit. During braking and hard acceleration, the strut rod is put into tension/compression. Rubber bushings allow more movement in this tension than poly bushings. Movement of the strut rod pulls/pushes the lower control arm fore and aft which results in changes in caster, camber and toe. Granted, these variations are very minor and are typically not of a magnitude great enough to be noticed unless your also getting hard on the brakes or heavy acceleration while cornering or have considerable amounts of driving experience at these limits to notice hte changes. For your average driver/cruiser, you won't notice these changes.
The caveat with poly bushings is that their thickness in the strut bushings and lack of compressability sometimes pushes the lower control arm into a position that won't allow the torsion bar to seat against the retaining clip. You can millor cut the bushing thickness down to compensate for this if you have the tolerance stack up that causes the problem. In the dozen cars I've converted to poly, I've never run into the problem, but I have seen it posted enough to know that it can and does happen.
