For me using the poly bevel all depends on the level of detail that you need, for example if its far from the camera and aint gonna be close in the shot then it wont really matter if the edges are sharp, where as if its going to be under scrutiney by the viewer than it really should be a bevel with say 2 segments (three edges) to get a nice round apperance as nothin in real life has a razor sharp edge (other than a razor LOL).
with your sign i would think is it close to the camera in the shot? if so bevel it with a segment 1 or 2 depending on how close it gets, also if its neon with a glow applied you might not need the bevel as the glow might obscure it.
Looks loke a nice little scene you got there arran, good going mate, post the results if you would sir!
"No pressure, no diamonds" Thomas Carlyle