I’ve had experience with both. It really depends what you need it for most.
The Bosch is a very basic machine with a very strong motor. The best part about it is that it comes with a cover so the flour doesn’t make a mess all over. It’s great for Challos. (I do six pounds of flour). I really does a great job mixing all on its own. You don’t need to babysit the dough. All you have to do it throw in all the ingredients and start the machine. It does a great job mixing.
The Magic Mill definitely takes up more room in the cabinet. The attachments for mixing connect to an arm that comes from the bottom and reaches over the top of the bowl. (The bosch connections are all on the inside of the bottom of the bowl.) Which makes it a bit harder to clean. There is no cover so you really have to be careful when you add the flour. With this machine you really need to stand and watch the dough/batter and make sure that it is getting mixed all the way. For instance you have to alternated between a little flour and a little water to make sure you get the texture you want.
One thing that’s important to know is that Although the Bosch does a fine job getting a stiff snow, there’s no arguing that the Magic Mill does a better job. Somehow the snow is fluffier and stiffer and has a better texture. (The Kitchen Aid would win hands down for the snow or cream)