I really really really really really really REALLY hate to say this. And I truly mean it. Its like trying to spit out rotten food. But chen... take a real good hard look. where is maemo now? where is harmattan? look at what happened with the ubuntu mobile... tizen...tizen is another example...sure it's relatively new ..but it is a good example of great design ..with its os with almost zero follow through thus far with its repertoire of available apps. Tizen is primed for turbulent failure. Jolla and Sailfish? ..."..." ....well...Jolla as Dave has pointed out has its problems... sailfish os ? ... I believe that in this world now... for devices and operating systems... and the software that run on them... that there is precious little time or breathing room for error, mistakes, lack of foresight, poor design, poor implementation, extended delays, lack of or poor support, and communication issues.... I think it is great that you ...Chen....are kind and thoughtful enough of those around you to ask what os should be the choice. And I will say this...as much as I absolutely hate to. You have a winning product that has taken a great deal of your time and doubtlessly your resources thus far.... Don't squander it. My best suggestion is this... Go with Android. It'll be a seller. Then ...once you have all those android users buying it up... The monstrous pool of Android users is where you should aim at. Its your best and smartest bet from a marketing and sales standpoint... Its just plain smart business... Later as you count the money in the vault... Then... you have the chance, funds and most likely fearless backing from lenders... to take risks .. and have the luxury of being able to take expected losses ...and at best ...(but unlikely) ...break even.. like aiming at os's with at most...a few hundred or a few thousand users to hope for sales from... out of a desire to be philanthropic... It's smart business Chen.... It should be Android OS . (god I hate Android)