I bought a 7" tablet from China. It's not a phone, wifi only, but an IPS screen (wide view angle, like iPad's) and latest and greatest Android 4, HDMI output too, and once my son-in-law and I had managed workarounds to get Google's market (now called "Play") on it, got Turboviewer Pro. I quite like 3D pdf to show stuff to customers, but neither Android nor iOS do 3D pdf, and not too many retail-level CAD produce 'em. I considered Flash, but iOS doesn't do it, Android is hit and miss, depending on version, and Adobe is saying that Android 4 is Flash-for-mobile's Last Stand. Autodesk's got an impressive publisher/viewer/animator for Inventor, but, honestly, $5K? Dwg, OTOH, is near universal. For the price point and performance, Turboviewer's right on the mark. I think the view styles are more pleasing to the eye for standard files than those that Acrobat reader does for .pdf, and the combinations of layer switches, renders, edge definitions, x-ray (transparency), lighting and views hit the sweet spots. IMO, price is very reasonable. The only time performance is a little sluggish, even on this single CPU-with-GPU 1GHz ARM 8, is loading rendering, the provided "reductor assembly" file taking about 20 secs to load the render, but after that, there's no hesitation in swinging it about. The only hiccup that I can see is that some fillet surfaces disappear/become transparent in rendered views without 2-sided lighting. Pretty impressive, IMSI/Design.