Shearwater. Only had positive experiences with them.
I accidently clipped someones car and they sorted that out efficiently.
I have had one breakdown under their policy and that was dealt with well.
NFU, I clipped someone's car and my sister took out the lockers on a fence!! Both claims were settled promptly, no increase in premium and no loss of NCB. We broke down once and recovery service was excellent.
Shearwater, Luckily I have yet to make a claim but the premium is very reasonable and the extra cost for recovery is much less than going to the recovery company direct.