The main difference between the Android versions and the BlackBerry versions is when they start reading messages.
With BlackBerry, both Vlingo and Drivesafe.ly both read messages as they arrive on the device. Drivesafe.ly has a better sounding voice for reading messages, but Vlingo (IMO) has better capabilities when you want to speak to the device.
On Android, both apps poll the email servers and read the messages directly from the server. They will check messages every five minutes (or however long you have the interval set). That can mean emails may not get read if the email app picks them up first, and messages will be read before they are actually received by the device. I haven't seen a way to get either app to read email messages as they arrive on the phone. Of course, with both apps, they read SMS messages when they arrive.
If you are also wanting to speak to your phone and have it send SMS, emails, make calls, and such, Vlingo will be a better option. Vlingo will also let you reply back using your voice.
When I had my BlackBerry, I used both apps. I preferred the way DriveSafe.ly would read messages, and the capabilities of Vlingo for converting speech to text (plus all the commands).
As far as bluetooth headsets, I think it is a limitation of Android, at least with 2.1/2.2. Bluetooth seems to get better with each update. I'm not sure about the bluetooth features with 2.3, but it may be able to read through the bluetooth, or at least accept voice commands/dictation.