Curve 8330, is there apps when running 5.0 os?

I haven't heard from anyone on this, when running 5.0 is there apps for that OS?

Yes, there are.

Is 5.0 any better than 4.5? I'm on 4.3 now, should I update to 4.5 or go for 5.0?

4.3 is ancient. 5.0 on the verizon 8330 causes chirps when calling. i just had to downgrade my friends phone back to 4.5.0.131 to avoid that.