I've recently had two German company cars. I've came from Japanese cars most of my life, so I'm slightly underwhelmed by them. Prior to having these I owned a Mitsubishi Colt and a mint 2006 MX5 2.0 litre sport. The biggest disappointment was a 2017 Mercedes Benz E220D AMG Line estate. It was a nice place to be I guess, the seats were fantastic, and that is a main part of a car. But I had the use of 2017 Nissan Navara prior to this and this had fantastic seats also, with superb lumbar support. The Mercedes is a nice looking car, it was huge, too big. Pretty dull to drive, not that quick, it handled pretty well for a big car, but you were totally disconnected from it. It also had a terrible squeak from the rear parcel cover. I rectified this by stuffing a piece of packaging foam between the parcel cover and it's mounting, I had to put it back in every time I removed this. Everybody to their own, I just didn't get it at all. It was like driving around in an armchair all the time. If I was buying this type of car I'd buy a Skoda Superb, I'm sure it would be better, the 2.0 litre VAG CR Diesel engine is superb. The rear run-flat Pirelli tyres were £265 a corner on the E-Class, they lasted 11,000 miles and I didn't drive it hard. I think I was expecting something amazing, more so driving a Mitsubishi Colt. What a huge anti-climax that car was, the badge means nothing at all to me with cars.
My current car is a 2018 VW Golf GTD. It's a lot better car in every respect. It's well built, goes really well for a diesel and handles very well. It's still a slightly vague/disconnected driving experience coming from an MX5, but that's to be expected. The engine is a belter, I don't know how reliable it is and I don't care because it's not mine. It's not as good on fuel as the 9 speed Merc was, but then again it's a way better drivers car, Audi/VW are nice cars, but overpriced. But then again it will retain more if you sell it. The Golf GTD is a Skoda Octavia VRS as far as I can tell, minus the boot, that's what I'd buy if it was my own.
I personally wouldn't buy a Mercedes, I think VAG are better cars. That's just from what I've owned and being a passenger in. I'm sure a 3 Series BMW Tourer would be a better drive than an A4 Avant though. Just depends what you look for in a car. I don't know what's the most reliable. I've read some bad things about German cars. I've never had any issues with Japanese cars.
The closest pass I've ever had on a bike was from a BMW 3 Series, probably coincidence though... I certainly don't think German car drivers are any worse than others..
If you've got the cash buy what you want. I just think it's a total fallacy that German cars are superior to other brands. Ford's impress me these days, as does my mother's Hyundai I10, what a cracking well built, excellent drive that is...