I'm on my 4th custom Vanson and I love them! I'm on the 3rd and 4th ones because I lost weight and the other couldn't be altered, not because anything was wrong with it. Their stuff is good quality. Are you planning on getting the pants that zip to it? The only complaint I have with the off-the-rack stuff is their 3 piece zipper arrangement. I hate it. They did it instead of offering full circumference so they could keep the adjustable waist band on the jackets. It doesn't look like a sturdy arrangement to me. I tried it on when I was at Vanson, and it unzipped itself pretty easily, and was very cumbersome to try and zip together. So, I went with a custom 2 piece so I could have a good full circumference one piece zipper. If the jacket does not have the adjustable waist band, they can match it up with a pair of sport rider pants and put a proper full zipper on it. Just a thought for down the road if you're considering pants. Other than that, good stuff!
Oh, and it'll last a very long time. They don't call them "heirloom quality" for nothing.
If you fit off the rack stuff, all the better. If you decide you want custom, I recommend going to Vanson and having them measure you. All of my customs have been a perfect fit. I've known a few people that had issues, but they were measured by staff in a Vanson distributor dealer, not directly at Vanson.