We have a 1640 but went to a demo of the 1650.
looks like they’ve ironed out a lot of the problems that still exist with the 1640 (that they should’ve just fixed there, that’s another story).
the sellable print speeds were still actually pretty quick. We took our own media’s down and there wasn’t any banding on the “production” speed for gloss and Matt.
as far as user friendliness goes, they’ve fixed a few things that bugged me, such as being unable to advance the media from the machine, the calibration now calibrates at every print speed instead of just reliance.
user friendliness, it’s the same as the 1640, if you’ve used a wide format printer before, it’ll be straightforward enough.
when we went to the demo (last week) the canon rep said double sided was still being worked on and the tolerances currently were about 1.5 inches. And it’s not as smart or “automated” as they lead you to believe. Also said there’s about 3’ of wasted material either side of the prints so if you’re offering d/s, make it long runs. (All this despite the fact they’re placing units in the field).
all I’ll say is, if there’s anything you’re not happy with, with that machine. Don’t expect canon to fix it, just wait until they’ve sold a bunch, failed to fix it then released a 1660..