I have posted this before but i will once again..
Older members here will remember all the trouble i had with my 3.2...To cut a long story short one thing that came up was the huge amount of burnt on varnish up the top end/cams etc. Head Audi tech told me "its this ****** long life Castrol" !! we are contracted to use it. We never had problems like this with Mobil , our last supplier... I notice now with my New S3 it has 2 service dates when you pull the trip reset. one for annual oil change and one for long life service ( less oil change)..
Oil doesn't really lose viscosity/degrade because of the time its in the engine. What it does do is get dirty and of course it then pumps that dirt round the bearings and pistons etc. However good your filter is carbon particles will get through and they wear your engine. Just look at the state of long life oil when its dropped out of the sump !!!!!! it get contaminated just the same as a short life oil but runs round your engine for twice as long.
Long life oil is fine if you are going to change cars every 3 years. You may not even change it and that is what its all about. Keeping costs down for fleet managers and making audi attractive to business users. what happens to it after the warranty runs out is not really their problem....Buy a good quality oil and change it minimum once a year. 6000k miles if you possibly can.