I just got the Mini Cutoff saw from Harbor Freight and spent an hour playing with it. It does a fast clean job. Not sure about blade life yet, but spares are cheap enough. Not bad for $30.
I do need to rig a little jig to serve as case stop and mouth support, but they even put the mounting holes in the right place to hold that. Main drawback I have found so far is that it does tend to spit out the piece that's cut off.
It's built a bit light for serious production work, but oughta work fine for us hobbyists.