I currently use a preventer rigged from the end of my boom and run to the bow and then back to the cockpit. I am considering fitting a boom brake as it looks a more flexible to piece of equipment use, especially when the wind has got to the wrong side of the sail.

Any thoughts or experiences people can share?

JG,
They serve different functions, overlapping for sure, but distinctly different functions. As one who believes the boom the most dangerous object on the boat, I have ours prevented at all times. For offshore we have an end of the boom system, for other times, the boom is triangulated and held fast by a side decks arrangement that also allows some control over planned gybes, but not as much control as boom brakes such as the Dutchman. I do not wish the boom to move unless I give it permission. Please see further the Fleet Surgeon 's advice on the publicly accessible portion of the Cruising Club of America on this issue and suggestions for implementing a preventer that is similar to mine.
More info if wished.
Dick Stevenson, s/v Alchemy