I've been looking, too, so I'll just jump in here as well...
Here's what I've learned so far (searching for a long-arm, big bobbin patcher):
Looking at new patchers is slightly more puzzling than figuring out which 441 clone is "the best." At least with the 441s (represented here), they're all made in the same country. With the patchers, you occasionally hear grumblings about metal-shavings-filled machines coming from the land of yellow stars (both the eBay primitives and Singer clones).
In a perfect world, we'd all be able to buy a Claes, 'cause those look the business.
http://www.cl-maschinenbau.com/leistungen/claes_kl_8346.php?lang=en
Sadly, they'll run you around five g's, slightly less expensive than a new Juki 441. I do not run a busy shoe repair shop (or any shop), so buying one would be insane on my part.
I asked my local dealer (a sponsor, but not a vocal one) about getting a used Adler 30-70. He said (1) they are rare, and (2) parts are impossible to get, so forget it. He suggested a Singer 29K. I see the 30-10 more often:
http://www.floridasewingmachines.com/product/adler-30-10-long-arm-19-patching-leather-shoe-repair-industrial-sewing-machine/
http://www.atlasortho.com/Adler-30-10-Patcher-Rebuilt_c_3945.html
...so people can get parts and are working on them)
I agree with Constabulary above: owning a nice Singer 29K72, 73 would be awesome. Do I have time to rebuild one right now? No. And I don't know if bigger ones are as plentiful as you would think. I talked to another of the LW sponsors and he said if you plan on using it for a while, go with a new one -- they're a little nicer than the vintage patchers and new parts do not always fit the old machines.
China vs Taiwan? Has Chinese manufacturing improved in the last few years, or is it the same ol' nationalist argument? Of course every dealer claims they have the best machine, and there will be a range of quality w/in a branded model ... so are we hearing about lemons, or typical attributes?
Right now, I'm looking at Landis's Singer clone:
http://landisusa.com/us-en/29-73.html
...which, of course, they claim is superior to the Chinese clones...
And they themselves look to be made by Taking in Taiwan: http://www.taking.com.tw/htm/product/2971.73-2971lb.73lb-7a-810.20.htm
They also have a slightly longer max stitch length and lift, which might come down to metric/standard approximations and how you see a range of maximum thickness in the 441 clones -- 3/4"–7/8" ... it depends how you set it up.
So my question is (finally): does anyone have experience with a Landis/Taking patcher? And, is Taking making these for Techsew?
In the end, maybe just base your purchase on who is the nicest on the phone and which machine has the coolest paint job. They're all fine, I'm sure.
Anyway, I should get back to sewing ... so I can justify buying another machine.
cory