Another thing I noticed: There seems to be a discrepancy (at least in some circumstances) between the sizes reported as transferred and remaining on the device, in the batch download page.

I was doing a batch download for Yahoo Maps, and the size available on device was decreasing at a rate 20 or 40 times faster than the size reported as transferred. I also think that the size reported as transferred was too low (around 65MB for 25000 tiles). I'll check the size of the files when the transfer is done, but I thought I'd mention this.