Flash Builder 4.5 -- native apps or virtual machine?

I'm very new to Flash Builder 4.5 and am still trying to get my head around it. I'm freelance and my primary code pimp has asked me to justify using FB 4.5 to develop mobile apps rather than something like PhoneGap or native SDKs (Objective C, Java, etc.).

I'm quite impressed with FB 4.5 and it seems quite plain to me that FB 4.5 tries very hard to provide all the tools necessary to create iOS/Android/Blackberry apps all from a single code base but I'm wondering a few things:

1) Does this require the use of a redistributable or virtual machine? I'm wondering both from a performance standpoint but also just to understand better how FB 4.5 provides this magic one-project-for-all-platforms capability. I'm guessing there must be some kind of virtual machine abstraction in use -- or does FB 4.5 generate a fully native application for each platform without the need for a machine abstraction layer?

2) Has anyone encountered a situation where any of the target platforms lack features or behave differently? E.g., "I cannot access some hardware feature like the accelerometer on Android under certain conditions."

3) Can anyone speak to the relative benefits or penalties that FB 4.5 offers relative to PhoneGap or other HTML 5 solutions?

1. Adobe tries its best to provide developers with tools to export their work to multiple platforms, including all the ones you provided above, so yes, it does provides "this magic one-project-for-all-platforms capability". You can scale the display to fit individual devices. Some sources claim that Flash for iOS compiles native applications but Wikipedia says flash for iOS is a 'just-in-time compiler' so I guess that's a virtual machine. http://en.wikipedia.org/wiki/IOS_SDK#Flash. I don't know anything about virtual machine-ish, so sorry.

2. Totally yes. Devices are made differently. The apps are essentially the same but some will or may behave a bit differently across different devices, even between Android devices. This question is a bit broad so for me, it's not much of the capability of the device or because of FB 4.5, but sometimes the screen and touch messed up a little bit because some phone manufacturer fails to do it right.

3. I don't have any experience in the other 2 so I can't say anything.

Thanks for your response.

I read the wikipedia page and it appears to be somewhat out of date. Also, the reference to a virtual machine in that section seems to be referring to the Flash Player (which AFAIK doesn't exist for iPhone) rather than an iPhone app created using Flash Builder 4. this article is probably one of the more authoritative ones that I've seen on the matter as it references specifically apple's decision to allow apps developed in languages other than C/Objective C/C++. I've been looking around and haven't found anything to clarify this one way or the other. I'm inclined to believe that FB4.5 is somehow building "native" apps but still am not sure.

That's what I've read most about Adobe onto Apple too, that they make native applications. So yea, they run pretty fast, some 3D games work.