It is worth the $70USD. These have the VIA 8505 chipset generally. These sell new without shipping about that much from China AliBaba vendor. These are the the very bottom of the tablets and is comparible to the MayLong or similar. Look at TipStirs posts and details. His posts if you review them can show what these can do.
Via and Rockchip devices are terrible in performance and usually pretty bad in build quality too. If you're buying on a budget then sure this is like picking up a G1 just to get you going with basic android stuff but don't expect the device to satisfy you for long.
I would recommend you seek out either a telechips device or something like a TI cortex a8 (usually labelled up as witstech or a81). For not much more money you get a lot more product.
As a final note, the pictures indicate as ever the trouble with letting the Chinese apply a brand name. In the UK we get told off if we use the irobot name (even an ebay listing will get removed) because that brand name belongs to a company that make an automated vacuum cleaner!