Ken...
Wow, Vaughn, great comparative review.
I have the Grizzly version (G0448) of the General. From the photos they appear to be nearly identical. It has a tilting head, but sorry to report I haven't used that feature yet so can't speak to it. The Grizzly comes with a stand, and it puts the table at belt height as with the General (I'm 5'8"). I find this to be convenient, as the workpiece is always above table height anyway, and I want to be looking down at the entry point for the chisel. The Grizzly has three handwheels, and the two table positioning handwheels are a bit close, but that would be true of all three machines. Not a show-stopper for me. I replaced a Jet JBM-5 with this mortiser, and have had no regrets. The workpiece vise and leadscrew positioning is orders of magnitude better than the JBM-5 (of course they're not equivalent in cost).
I agree with Tod. I have mostly Grizzly machines, not just because I like the quality (usually), but Muncy is within range of me (bit of a hike) and Grizzly's customer service is unsurpassed (in my experience, anyway). That can definitely be a deal breaker.
Good luck.
Cheers.