Evolution is the only client on Linux (that I’m aware of) that fully supports Microsoft exchange and Google out of the box without any plugins. I used thunderbird for a long time, however I got frustrated so many times after things broke after every update because essential plugins stopped working. Yes, you may say Evolution UI is old, but the software is rock solid and softwares in general are more than their GUI. It’s good to bring awareness about the tracking but I’m not so bothered by it, as its hard to find software that doesn’t track you these days