This is why I've stayed with the software that came with my car last June, and not done any updates.
My USB music works perfectly (although I gather larger numbers of tracks than the 300 or so I have cause more problems), the left right buttons on the left set of steering buttons change tracks no problem.
In 12,000 miles I've only had the SatNav change to Km once (but I hardly use it because of the poor traffic and dreadfully out of date maps, and because my TomTom with lifetime quarterly maps and live traffic is soooo good...
I've turned all sound from the SatNav off so have no problems there either.
I agree the speed limit recognition isn't even good enough for Alpha testing, and niether is the auto lights or auto mainbeam. But overall, this is the best car I've ever driven, never mind owned.