Not really a question of "best" but more of what you are looking for. I personally have an Akra slip-on with N55 midpies and wireless kit. I love it because it allows me to set the sound to a closer to stock tone with a more "round" rumble, and to open the valve for a roar when I'm driving up the mountains!
I haven't heard the Eisenmann but the Meisterschaft sounds great also. It's just that what you hear is what you get 100% of the time. If you like loud all the time, it might be beneficial for you to spend less $$$ on a Meisterschaft but for me it was worth the extra bucks to be able to open/close a valve + get very good craftsmanship IMO.