Android and iOS continue to sit pretty atop the US smartphone market, according to a recent NPD study. The current titans of the mobile industry both saw their pieces of the OS pie increase in Q2 of 2011, putting Andy Rubin's green robot in the lead with 52 percent and Apple at 29 percent. Newly adopted webOS, and Microsoft's WP7 and Windows Mobile all managed to cling to their respective 5 percent shares with no yearly change, leaving only BlackBerry OS to experience an 11 percent decline. But the real meat and potatoes of the report focuses on Google's soon-to-be in-house partner: Motorola. Despite the rosy picture painted by recent acquisition talks, the company appears to be facing tough competition from Android OEM rivals, and the wireless market as a whole. In regard to overall mobile phone share (read: dumbphones, et al.) and smartphone-only, Moto saw a 3 percent year-to-year decline, with its biggest loss coming from Android unit sales -- a 50 percent drop to 22 percent of the market. Will the rosy glow of Mountain View "help inspire new paths to differentiation" for Moto, or are we just looking at a repeat of the "RAZR era?" While you ponder these pressing questions, head past the break to read the full report.