The powerline version is available as a single pack and are cheaper than the on track models per wagon
On track models come as a three pack
The powerline version has doors that do not open where as the On track models have opening doors and interior detail ,
The Powerline version has a black underframe that should be the same colour as the body so will need painting to match , On track have got this right
As for running qualities i dont own a powerline VLEX so can not say myself but the On track models VLEX you could not ask for any better running quality from a RTR model
My money would definatly be on the On track version , they are a little bit more to buy but well worth it
And as advertised powerline say "a good finish" and Ontrack models say "A great finish"