I have a Galvin Jacket (plus a few other non waterproof items like trousers etc) and I have to say the quality is exceptionally good, the GoreTex is, obviously, perfectly watertight and the attention to detail superb. That having been said I also have an Aqaulite suit from ProQuip that I bought from The Carlisle Golf Centre which is superb - light, quiet and breathable - and I could have bought three full suits for the same price as a Galvin Jacket!
All in all, if you are playing in really bad weather all the time in the winter, the GG is the absolute business - but I recommend checking out the ProQuip first (also I believe they are based in Scotland, although I think they have just been bought by Edinburgh Woolen Mills. Its the same manufacturer that helped the US Ryder Cup team out when their Sun Mountain suits didn't make the grade (allegedly!)
Hope that helps.