After looking in to buying a Road Angel I decided to write a brief guide to make things simpler for you guys.

 The range stands in order from the bottom up as the Road Angel:-
Classic,
Compact,
2,
Plus,
Navigator,
6000, 
7000.

 The Classic, Compact, Road Angel 2 & Plus are stand alone camera detectors, but the Navigator, 6000 & 7000 are the Sat Nav versions with built in camera detection.
-----------------

 With regards to the main differences between them and which one you should buy,
the Classic is the first one with a seperate laser detector, Blacksopt revised the PC connection from Serial to USB to make it more PC compatible.

 The Compact is smaller than the classic, with an optional laser detector add-on, an optional upgrade to include camera sites in the EU and the addition of being able to pick up the London conjection zone & show the speed limit at the camera sites just in case you forget.

The Road Angel 2 has built in laser detection as standrd, but doesn't show the speed limits.

The Plus has a built in battery (8 hour) so that you can charge it up and use it on a bike or car without plugging it in, there is also a waterproof case available for motorcylists to use it in the rain.It has all the features that the others have, other thansupport for  EU camera sites.

The Navigator, 6000 & 7000 are a bit more complex, but basically they vary in battery life from 4 hours on the Navigator to 8 hours on the 6000 & 7000, the 7000 supports updates via Bluetooth and is also waterproof for the bikers.