These readers have problems or serious limitations.

USB descriptor: readers/ACR122U_PICC.txt
Manufacturer URL: ACS ACR122U PICC Interface
Features: contactless
Limitations: No extended APDU
Time extension requests are not supported.
Firmwares version < 2.06 are bogus: APDU with 0x7B (123) bytes expected do not work with a 14443 card. The reader returns SW=63 00 instead.
In CCID release: 1.3.9

USB descriptor: readers/ActivCardV2.txt
Manufacturer URL: ActivCard ActivCard USB Reader V2
The reader do timeout when a special USB frame is sent from the reader. If the frame size if a multiple of wMaxPacketSize the communication is stopped.
Some users report that this reader is in fact a SCR-331 with a different firmware and that you can upgrade its firmware to transform it into a (supported) SCR-331 reader.
In CCID release: 1.0.0

USB descriptor: readers/Aladdin_eToken_PRO_USB_72K_Java.txt
Manufacturer URL: Aladdin eToken PRO USB 72K Java
The token does not work after a warm reset. See http://www.opensc-project.org/pipermail/opensc-devel/2009-April/012128.html
In CCID release: 1.3.9

USB descriptor: readers/ATMEL_VaultIC460.txt
Manufacturer URL: ATMEL VaultIC460
Features: ICCD
Limitations: No extended APDU
The reader does not send time extension requests. The driver times out after DEFAULT_COM_READ_TIMEOUT (3 seconds by default).
In CCID release: 1.3.12

USB descriptor: readers/Broadcom_5880v2.txt
Features: Multi interface reader
Found in Dell E6400 laptop
The reader reports "Hardware error" to GetSlotStatus when no card is present.
http://ridrix.wordpress.com/2009/10/13/how-to-enable-pcsc-support-for-dell-contactless-reader/
In CCID release: 1.3.12

USB descriptor: readers/Broadcom_5880v2.txt
Features: Multi interface reader, Second interface
Limitations: No extended APDU
Found in Dell E6400 laptop
The reader reports "Hardware error" to GetSlotStatus when no card is present.
http://ridrix.wordpress.com/2009/10/13/how-to-enable-pcsc-support-for-dell-contactless-reader/
In CCID release: 1.3.12

USB descriptor: readers/LTC31.txt
Manufacturer URL: C3PO LTC3x USB
The reader works fine with Linux kernel 2.4 but does not with Linux kernel 2.6. The ioctl() syscall returns EINVAL (Invalid argument). This reader is not more sold and replaced by the LTC31v2 model.
In CCID release: 0.1.0

USB descriptor: readers/Feitian_SCR301.txt
The reader fails with a CASE 2 APDU with Le=0 (256 bytes)
Sent: 80 34 01 00 00
ifdhandler.c:1219:IFDHTransmitToICC() no name (lun: 0)
commands.c:1542:CmdXfrBlockTPDU_T0() T=0: 5 bytes
-> 000000 6F 05 00 00 00 00 07 00 00 00 80 34 01 00 00
<- 000000 80 00 00 00 00 00 07 40 FE 00
commands.c:1316:CCID_Receive Card absent or mute
And time extension requests are not forwarded back to the host.
A new version of the reader is available and may fix this issue.
In CCID release: 1.3.11

USB descriptor: readers/Gemalto_IDBridge_CT30.txt
This reader is a new version of the GemPC Twin but with firmware E.
When connected to a USB > 1.1 port the reader do not respond correctly to the PPS command or the SetParameters after the PPS.
In CCID release: SVN

USB descriptor: readers/HPUSBSmartCardKeyboard.txt
Manufacturer URL: Hewlett-Packard Company HP USB Smart Card Keyboard
Features: PIN Verification, PIN Modification
SECURITY ALERT: Martin P. reported that on Mac OS X the pinpad feature does not work correctly and the PIN code is sent to the host (instead of being kept secret by the pinpad)
In CCID release: 1.1.0

USB descriptor: readers/HP_kus-0133.txt
Features: PIN Verification, PIN Modification
WARNING: Secure Pin Entry feature is bogus and has been disabled.
firmware < 1.24 is bogus. SetParameters fails with a card of ATR 3B 16 96 41 73 74 72 69 64. The smart card reader part is from SCM.
In CCID release: 1.4.1

USB descriptor: readers/mIDentity.txt
Manufacturer URL: KOBIL Systems mIDentity M
Limitations: No extended APDU
Time requests are not managed correctly and make the firmware fail. This is not a problem unless you use a time-consuming APDU like RSA key generation.
A new firmware will correct the bug.
In CCID release: 0.9.3

USB descriptor: readers/mIDentityXL.txt
Manufacturer URL: KOBIL Systems mIDentity XL
Time requests are not managed correctly and make the firmware fail. This is not a problem unless you use a time-consuming APDU like RSA key generation.
A new firmware will correct the bug.
In CCID release: 1.3.9

USB descriptor: readers/Oz776S.txt
This reader is common as an internal reader in laptops like the Dell D420 or D820.
The ATR may be corrupted by a 90 00 at the end
The reader is bogus and does not accept PPS
In CCID release: 0.9.3

USB descriptor: readers/Oz776_7772.txt
This reader is common as an internal reader in laptops.
The reader is bogus and does not accept PPS
In CCID release: 1.3.1

USB descriptor: readers/Precise_200_MC.txt
Manufacturer URL: Precise Biometrics Precise 200 MC
Features: biometric
Must be firmware version 50.00 or above: time extension requests are not sent back to the host in earlier versions of the firmware. The reader can't talk to card with TA1=96. See http://archives.neohapsis.com/archives/dev/muscle/2010-q3/0197.html
In CCID release: 1.3.10

USB descriptor: readers/Precise_250_MC.txt
Manufacturer URL: Precise Biometrics Precise 250 MC
Features: biometric
Must be firmware version 50.00 or above: time extension requests are not sent back to the host in earlier versions of the firmware. The reader can't talk to card with TA1=96. See http://archives.neohapsis.com/archives/dev/muscle/2010-q3/0197.html
In CCID release: 1.3.6

USB descriptor: readers/sid800.txt
Manufacturer URL: RSA RSA SecurID (R) Authenticator
the new firmware (revision 6284) fails to respond to initial CmdGetSlotStatus() with "ccid_usb.c:687:ReadUSB() read failed (5/2): -8 Success"
or with "<- 000000 81 FB FF FF FF" "commands.c:1046:CmdGetSlotStatus() Not enough data received: 5 bytes"
In CCID release: 0.9.4

USB descriptor: readers/iDream.txt
Limitations: No extended APDU
also known as ID-SMID01, SCT018 and maybe other commercial names
With the old firmware, PPS fails with a Cryptoflex card Powerup fails with a Setcos card
In CCID release: 1.1.0