Jim,
"Yes, I did read that in your first post, but didn't take on board the full implication."
May I suggest - RTFP twice?
The Netgear WILL work better for you in your scenario, but only with a max of 3 PCs and with only UNIDIRECTIONAL support. The OP was looking for bi-directional support for an unspecified number of users.
Keef,
"It works sort-of: the first faff was that it wants to be 192.168.0.10 and if you need to use anything different (which I do) then you have to read the instructions for your computer - not for the device. Since there weren't any instructions for my computer (ever), I told the router about this orphan device, and all was well on that score."
If you read the instructions, it uses dhcp unless there is no dhcp server available. in which case it defaults to 192.168.0.10. It has to have an IP address, after all.
"That done, and the software having installed itself about four times (no idea why, it just wanted to), the desktop and the laptop could print through it."
If you're running Win 7 install as admin and once installed run in compatability mode for Vista SP1.
"It seemed quite happy to have my high-speed USB hub connected to it, and could see that there were devices there."
Good.
"Snag one: the USB scanner wasn't in its vocabulary. That was an "oh bother". I didn't connect any of the other potential "shared USB devices" pending further investigation."
You're under a false impression here - it doesn't have a "vocabulary", library or database - it simply presents the connected USB device to the PC on a virtual USB port. It is up to you then to provide it with the necessary drivers, just as if you had attached the device directly to your machine. Obviously, you must do this after selecting "connect" in the software and on each machine.
"The second snag was the faff to use it. Having to start the software, connect, print, disconnect and shut down the software each time proved too much of a pain after about ten minutes."
This one really makes me wonder what sort of operation you're running - SOHO or enterprise? Firstly, you can set the "MFP and Storage Server" utility to run at start up if you really think that a second or two for it to run is that bad. Connecting takes a similar time, as does disconnecting. As for shutting the software down afterwards.....are your machines really so lame that this little exe can't be left running?
I must tell you that I'm most disappointed with your posts. I offered the OP a realistic and cost-effective solution for his requirement for a bi-directional print server. Despite a personal offer of assistance if required, you have sought to rubbish the product without taking the time to read and digest my post or the manufacturer's instructions.
I have no connection to TP-link or the products. I only offered information with the best of intentions. I shall think twice in future.