I've just bought an audi a6 to replace my lexus GS.
The build quality of BMW and Audi were nowhere near as good as the lexus, I found.
Standard options are much better, and the trim levels much higher.
You have to spend a fortune to get the same level of ventilated seats, walnut, etc.
Even then, I had to lose out on things like fancy suspension, soft close boot, rear sun-visor, etc.
When they all come standard on an SE-L, you're happy, but when you have to specify them all, you can't justify the extra cost.
On the other hand, the audi's technology and looks far outstripped the lexus in some areas.
Haven't seen much of the new GS, but didn't get a whff that LED lights would be there, HUD, or the same level of online services.
Maybe I'm wrong, but I fancied a change anyway.
Will dearly miss the GS though!