I've been looking for a low cost hobby level oscilloscope for quite a while now. Entry level oscilloscopes such as the Rigol DS1052E start at around $400 which is way more kit than I need for my occasional tinkering, but without an oscilloscope it is practically impossible to work on some projects.
I considered the low cost DSO Nano which is very affordable but I have read so many mixed reviews and it just seemed too small to be very practical, so I kept looking.
Then I started looking at USB oscilloscopes. These connect to a computer via USB so that the computer can act as the user interface, keeping the cost of the oscilloscope down considerably. After extensive research I found the BitScope Micro which was just launched earlier this year. This is a stripped down version of their product targeted at the amateurs and hobbyists like myself.
The free software supports Linux, Mac and Windows and can even run on the Raspberry Pi! I ordered mine direct from BitScope (based in Australia) but it is now available to order directly from Amazon. In terms of features, the thing I really liked about this scope is that it is a dual channel oscilloscope and also has a 6 channel logic analyzer, making it possible to look at up to 8 signals at the same time. The capture rate is 20MHz which is more than enough for the projects I am interested in (mostly audio frequencies so 44 KHz or lower).
Here is a screenshot of the dual channel oscilloscope mode. Here I am using cursors on the screen to measure the amplitude of a signal. I have been able to accurately measure signal frequencies as well.
This is the first oscilloscope I have used since school (20+ years ago) so I can't provide any comparison to other products but I can say that this is now an invaluable tool for me and the software has worked flawlessly both on my Linux desktop and Mac laptop. The documentation is available as a free download in PDF format and was simple enough for me to follow.
The only downside I see is that for higher frequency signals the screen refresh rate may be quite slow, but that also depends on the specs of the computer you are using. It's also worth noting that this is their entry level scope and they have many other models which are perhaps more capable.
I would highly recommend this for fellow Arduino / electronics tinkerers!