Vipec is by far the better option just in terms of customer support, Autronic fail horribly on this front.
I personally love the Autronic though, and wont be swapping my SM4 for viped, Im too used to it now and I really do prefer the mapping interface on it as well (think even sheady does TBH, its very good once you are familiar with it)

As MikeR mentions, Sheady is the UK's leading authority on both these ecu's and hence the only person worth listening to really!

Both will work on cossie sensors, although they run their own map sensors instead (autornic is internal, not sure on the vipec) and I think Mark will prefer using a quicker reacting airtemp sensor than the cossie one.