I purchased 6 USB erupters recently and went with the Juiced Systems USB 3.0 / 2.0 - 13 port USB HUB:
http://www.amazon.com/Juiced-Systems-USB-3-0-2-0/dp/B00B1WMYGO/ref=sr_1_1?s=electronics&ie=UTF8&qid=1376614790&sr=1-1&keywords=Juiced+Systems+USB+3.0+%2F+2.0+-+13+port+USB+HUB+5v+Power+Adapter A 3A adapter is included and I only planned on running 6 erupters in the short term, so I figured this would be a hub well matched for my setup. When I first had it connected and running there were no problems or hardware errors. The setup ran steady at 2 GH/s for a day or so before one of the devices starting giving continuous ICA invalid nonce errors. I restarted cgminer and was immediately flooded with errors for the same device. I moved the USBs around, rebooted, etc etc and can't get the hub to work with 6 erupters at this point.
So I started running 5 erupters... after about a day the same damn thing happens except cgminer is complaining about 2 of the 5 erupters. I restart cgminer with just 3 erupters connected, and I get these errors:
[2013-08-15 20:45:54] Icarus Detect: Test failed at /dev/ttyUSB0: get ffffffff,
should: 000187a2
[2013-08-15 20:46:46] Icarus Detect: Test failed at /dev/ttyUSB1: get 00000000,
should: 000187a2
Sometimes the host is seeing 0000000 for 2 of the erupters, sometimes FFFFFFFF, sometimes 1 and 1 as shown above. Sometimes it will start without error codes, but give the continuous invalid nonce errors after a few seconds of operation. At this point I can only reliably run 1 USB erupter in my fresh Ubuntu host with cgminer 3.1.1 (compiled with icarus support of course) and the latest version of bfgminer. All devices are linked in /dev. I have also tried my Windows 7 host with proper drivers and cgminer 3.1.1 with the SAME result. In the Windows host, all devices are assigned a COM address and any single erupter will work, but with 2+ connected through the Juice hub it will either give the 'get 00000000' error or loop into the invalid nonce sequence.
I guess I'll be off to Best Buy in the morning to find a random powered hub to try out.