looking for my first mill...

[Darrel]

The crank mills I have seen use a rope to pull the mill head through the log. So if you should choose one with the crank just untie the rope and push it on through a few logs. If you don't like it retie the rope, easy peasy. As for one being better than the other, as far as I know, the one you like is the better. Personally I don't like turning a crank all day, it makes my elbow hurt. Some folks really like the crank. 

I'm not knowledgeable enough to address bolts vs welds.