The one thing that gets right up my nose is (and this seems to happen more often on A/G radio) you turn final and want to make that call, and then some charlie sparks up on the radio with his full life story - knowing full well that they're not going to get any kind of response.
I would say that any issues are not the fault of the ATSU, FIS, or A/G radio but just that pilots don't know how to use the different services effectively, efficiently, and succinctly.
I have to say that I also feel sorry for the controllers at Farnborough. They seem to get tom, dick, and harry calling them up. Using Benson (if you are north of Farnborough) can be much better as they are usually much quieter - reduces your stress levels significantly, and helps reduce the workload on the F'boro ATSU as well.