I "mash", so I like the longer cranks, but I'm not sure it makes much difference. If you think of cadence as feet per second going around the circumference of the crank circle. Then, circumference = πd = 2πr. So, as you increase the crank length, you also increase the crank circle and necessarily reduce cadence. Thus, you get more leverage, but with a slower cadence. It probably all ends up in a wash.

I still like my 180's though

I don't know about durability. I just cleaned and lubed a Sachs 3x7 Dual Drive, and at least the main assembly was very simple to tear down. Of course, the Alfine has quite a few more parts.

I would, however, be a bit afraid of one blowing up in the middle of nowhere, at least until it happened to me once. You may gradually loose gears. A normal derailleur system can often be kludged to make a single speed.