The ScanGuage/UltraGuage and the Torque/Android setups are two different beasts. The Scanguage is designed to be installed full-time and allow continuous monitoring of OBDII output. It has a tiny screen with limited graphical ability.
The Anrdoid system is surprisingly rich. I have the full Torque version installed on my Acer Iconia 10" tablet and a cheapo Chinese wired OBDII dongle. This is not something you can just leave hooked up, but is pretty good if you need to do diagnostics. This is replacing my ancient BR-3 that only works with a serial port and the last laptop I had with one of those died. It also would not work on newer Canbus cars.
The dongle was around $25 and the deluxe Torque is all of $4.95. So you can't beat it for cost if you already have an Android machine. A tablet is ideal. Any laptop solution will cost you $$ for the software. I tried all the free ones and they all stink.
Torque will let you graph O2 sensor output, although I have not figured out if it can do two sensors at the same time. If you really wanted to leave it hooked up, you can do some really cool displays, even integrating the accelerometer and GPS on the tablet. Graphically, it's way beyond what the itty-bitty ScanGuage can do. But I just want to do some simple diagnostics from time-to-time and its a great solution for low $$. Great for pulling and resetting codes.