Heh, lucky for you, I've owned both (the Milwaukee Fuel for the past year, and just recently a Metabo brushless).
The Metabo is built much nicer as you would expect, made in Germany, about a pound lighter for the same power. It has an electronic clutch, so instead of clicking and clacking when you reach the torque limit, the drill just stops. Metabo has multiple drill offerings, that range from 500 in-lbs to 1000. I have the BS18 LTX BL which puts out 797 in-lbs, and it's 4 lbs on the dot. The impulse function is nice for removing stripped fasteners or drilling on tile, I haven't used it yet though.
The quick release chucks are very nice to have, you can swap between the 1/4" hex bit holder (which is built around the Wera Rapidaptor) and the Jacobs chuck in seconds, allowing you to pilot drill and drive with one tool. A right angle chuck is also available, and they make a 3x torque multiplier chuck as well, but it's near impossible to find in the US.
The only gripe I have with the Metabo is that the soft start motor makes it harder to accurately pulse w/ the trigger.
The Milwaukee is really nice as well, I'd say best of what you can find in a big box store. The chuck is kinda ****, but you'd only realize if you're drilling big things. The balance is good, weight could be lighter. The ability to run it on the smaller 2.0Ah batteries is nice, although it makes the balance not so great.
In the end, the Milwaukee is a great tool, the Metabo is a premium tool, and you pay for the difference. I don't think anyone would look at the two and think the Milwaukee is the better tool.
The Milwaukee does 90% of what the Metabo does for much less money, but if you're using it all day or you appreciate the small differences in details, you'll love the Metabo.