Bought an Origin B2, and had it professionally fitted, together with a laser diffuser that returns the beam for 5 seconds, whilst you slow down.
First day out, there was a Bobby on the M4 with a laser gun. The system gave me a good fore warning, and bleeped like mad.
Well worth the outlay, and the B2 is much neater than the Road angel, which looks awful on the dash. The laser deflector peeps out through a cut out in the front grille, and is virtually invisible.