The Tektronix documentation indicates that the TDS series scopes are in fact multiple series but a note in this page suggests otherwise.
I have a TDS2012B and it's great - after 10+ years without calibration, the frequency counter is still spot on reading 10.000MHz from my reference.
I was going to start splitting out this page to help - but I thought I should drop a note in here while I read around and learn more.
You'll be kicking me for spelling colour here - I'll try to get myself to get over the grimacing and use another spelling for the final cut! TDS1000 series 2 channel with monochrome display TDS2000 series 2 channel colour
TDS1000B series 2 channel monochrome with USB IO and VISA TDS2000B series 2 channel colour with USB IO and VISA