Take it from a guy who bought a bitscope BS310U a few years back:
**broken link removed**
The software can completely make or break the whole thing. If the software interface is a pain to use, you're probably not going to like your scope. My bitscope sits on a shelf and I only use it a couple times a year despite frequently working on projects where it would come in handy - and it's largely because of the terrible software interface. The software for the scope you linked looks pretty cheesy at first glance, so I would be wary if I were you.
Their specs also sound shady as you guys have noticed... Having always worked with nice expensive DSO's at school and work, I didn't take a close look at the specs when I bought mine, and I realized quite quickly how bad an 8-bit ADC can be in an oscilloscope, especially when you're stuck spreading that 8-bit resolution over too large a voltage range for what you're measuring because of the hardware. A nice clean square wave at 5v can end up looking really noisy. I'd also recommend making sure that that scope can capture on both channels simultaneously. I was very disappointed when I discovered that mine can't, it makes it much less useful for one-shot captures which I use a lot.
And of course, be wary of their 100MHz claims. It is not clear if they are confusing 100Ms/s with 100MHz signal capability (which would be wrong), or if they're saying it has a 100MHz analog input bandwidth, which is just the bandwidth of the analog buffer/amplifier/etc circuitry between the probe and the ADC's.