highlight reflections with white plane or vray light plane?

[lukx]

what do you think is better to use for highlight reflections on cars or other metal surfaces, white planes with vralight material assigned or just vray plane light?

[McMaster]

I would say a simple plane would save a lot rendertime compared to a light!
And in reality you often have not got multiple lights reflecting (you just have one sun), the objects causing reflections mainly are light surfaces (houswalls, ...)