1. Android has Android Market, and I know WinMo has its own market too, what about Symbian?
And do WinMo's market offer free apps too?
Symbian does not have a centralized market. But, for Nokia Symbians, they now have OVI store. Symbian apps are easy to get anyway so they dont need market i guess

2. I understand that Android Market is expanding fast, but currently, which OS do you think provides the widest range of good apps?
Android has about 10k apps. Iphone has about 100k apps. Symbian has more than iphone When you say "good apps" it depends on what you mean by "good" coz Symbian does have some really cool apps too tbh But iphone and android have good accelerometer integrations compared to symbian.

3. Devs complained that the Android Apps are hard to develop because of the wide range of machines and different screen sizes adapting Android OS.
But what about WinMo and Symbian? Only iPhone OS has one and only device, so what makes Android so hard to develop for different devices?
That is not true. Those devs who complain are just noobs. Thing is, Android market is filled with quite a number of "cheap apps" which in other words mean fugly looking apps promoting indirect sexuality and nonsense like wallpaper which you can change yourself. iPhone verification process is of very high standards. So their apps are of high quality in the market.

If u want to talk about hardware stuff, there are too many differences. Talk about camera, bluetooth, loud speakers, touch sensitivity, multi tasking, Internet speed, There are tonnes of differences. To me,im sick of iphone coz they never change the design. No longer using symbian because because i want a change after using symbian for about 7yrs. Choose google because i use google like crazy. I did a lot of reading and testing before choosing my phone and i have to say, im very happy with hero.

BT file transfer is not part of Sense UI..Its part of the Google SDK..