Out of the two personally i would go for the B2, from what i know it has more features, but you have a fiar few wires, all of which can be easily hidden behind dash. RA as far as i know again has less features but its an all in one unit and can be easily moved from car to car.
You will have a heat reflective windscreen so might run inot probs wiht the RA, but the B2 antenna can be placed anywhere, think Lee has it in his back window.
You also have the option of a B2 Solo, which is an all in one origin B2.
Also whihc i like the look of is a micro road polit, hasnt been out that long, not sure now it performs, but it is sooo small