The ML-2010 problem has been fixed for me Installing the usbtb usb backend for CUPS.
The procedure I followed:
Download and install from the gutenprint page http://sourceforge.net/projects/gimp-print/files/ the two packages gutenprint-5.2.9.dmg and usbtb-1.0.17.uni.dmg. Actually the gutenprint driver doesn’t support the ML-2010 but without it the usb backend didn’t work for me.
Install the official Samsung ML-2010 driver.
Reset the printing system - http://support.apple.com/kb/HT1341
Add a new printer (+), wait 20-30 seconds and the Samsung ML-2010, Type USB Printer (usbtb) appears in the printers list, next to the usual Samsung ML2010, Type USB.
Select the new one and manually choose the Samsung ML-2010 official driver for it.
My old Samsung printer is working very well now, much quicker than before.
It seems the printer Intermittence was due to some issue on the usb layer communication, from the Samsung Driver and the CUPS server.