Its just preference. Many people give the exact same stories as yours with BMW and Mercedes reversed, it all depends on what cars you get (all those you mention are over 10 years old), what your priorities are etc.
All your dislikes about your Merc have plus sides to those of us who like them. The not-so-smooth gearshift is also very quick to change, quick reacting, and doesn't suck the torque like BMWs autos are known to.. matter of preference
No ride quality mentioned - ever compare E30 3-series to 190E? One is tuned for ride, the other for handling.. you presumably prefer the former, many prefer the latter
Cant balance the tyres? come on!
And of course, there are those who will ask you to compare both cars at 250,000 miles (or if one of them will even be running at that)
IMO: Just enjoy driving whatever you have and try not to worry about the grass on the other side of the fence