Have not had a chance to try the courier out in combat yet but with this build you can see that it may give some competition to the vulture with a much lower cost to boot. I am sure in most cases the vulture will fry this thing with its class 3's but given the element of chance, the courier looks to be a bit of a mini beast in my opinion.
here's a build i did for example
http://coriolis.io/outfit/imperial_courier/24A3A3A1D3A2D3C1a1a260404000m584027272725
That concerns me a bit. My vulture has A5 shields AND A5 thrusters and can hit a higher boost speed (a comfortable 390+) than your courier. The fact that it's not nearly as maneuverable (at least according to listed stats) is concerning too.
Why the blazes did they make the courier so slow? Another thing that would make smaller fighters more relevant would be to give the viper the turning ability of the vulture...