Shielded motor leads are a great improvement in the VFD world but, as usual, the marketing people tend to run AMOK with some of the claims. With regard to radiated noise, expect a big improvement. With regard to protect of the motor insulation due to ringing voltages and reflected wave, expect no change. If you have long motor leads, you will need a line reactor, dvdt filter, or sine filter pretty much the same as if you have run THHN in a metal conduit. With regard to common mode noise or ground noise, the problem is made a lot worse with the shielded cable due to the increase in capacitance to ground. If you have short leads or if you have a solidly grounded wye 480/277V power supply, or if you have a drive isolation transformer, this difference may not be significant. On the other hand, if you have a floating delta power source or high impedance grounding, or maybe even a lack of a grounding network in your facility, then the motor lead cable can actually aggravate an already bad problem.