Oxygen sensors are oxygen sensors - that is, the electrochemistry of how they work is the same regardless of who makes it. There are heated (usually four wire) and unheated (usually two or three wire) but any of them will fit the bill. generally they run about $65-75 bucks at the parts stores, so why are you fellows paying more?
As for output there are numerous output gauges that are dirt cheap for an oxygen sensor. I use a Cyberdyne that displays a bar graph from rich to lean. About $65 and I'm sure cheaper than anything MoTec makes - heck, $65 might not buy anything from Motec. Anyhow, the Cyberdyne works well and allows me to tune the car.
As for output, well, all oxygen sensors output a measurable voltage that is from 0-1V. The gauges just interpret that for you on a graph, gauge, or, in the case of this "expensive" Motec gauge they just display the output to you with no interpretation - odd if you ask me. So, if you like you can simply use your volt meter and get the same info (there might be some impedence issues but on the whole it works okay).