If you're sitting on the motorway most of the time, an auto won't be much benefit unless you really need one.
But then a manual wouldn't make an difference in terms of experience.
Like fox said, if you sit on motorway at a decent time of day then you select top gear and cruise.
I maintain that for perhaps 95% of driving having an automatic is either superior or just as good as a manual, but it is the 5% of the time where not having complete control over gear changes is utterly infuriating is the one and only reason that my next car will be a manual.