My company sells/reps for vangs from all the manufactures that have been discussed here. This is not a solicitation for sales! The best bang for the buck is definitely the Garhauer vang. They offer the best purchase and price, both of which are of utmost importance.
As a matter of fact in sailing aboard a Beneteau 52 recently I noticed that the Garhauer vang over-powered the boom. This would be the only concern with the Garhauer product...don't over-do it and break a gooseneck, a casting, a boom or otherwise...keep the tail off wiches! I have raced and sailed on many different sized boats with Garhauer vangs...always a good choice...a little weighty...but a good performer.
Great product....
Rob