The Vedder is not the best testing local for a pair of waders because just about all brands hold up quite nicely because of the easy terrain getting to the river. It's the tough hikes, going down steep canyon hills, and bush bashing that's the true test of a good pair of waders which makes the fit that much more important. Check to see were the seams are. If there's a seam running down the inner thigh it usually spells trouble and as mentioned above the lenth of the leg is super important as well. A low crotch is also a recipe for leakage.
I used a pair of Simms lightweights for 4 seasons (over a 100 fishing days) and never had a leak from the knees down, only had leaks in the butt section of the waders from sliding on my my friend down icy, rock hard snowy slopes on the Thompson which trust me, I had no intention of wanting to do. The greasy steep hills in the Chehalis canyon and the Gold are equally as treacherous. My guides have held up much better to that type of abuse because they are made from thicker material.
Conversely my buddy had the older blackwaters (Bare) and he is quite certain they began leaking on the hanger in the store when it began to start raining outside. Three returns later he was finally given the latest model which appear to be working better for him. The Guide G3's are awesome waders ( very pricey though). However, you do not want to be at the bottom end of their bootie size. I bought a pair of mediums which come with a 9-11 size stocking foot. I am a size 9 so my foot is swimming in them so they are a bad fit. Watch out for this because any pinching of neoprene in the wader boot will also cause leaking. Hope this helps.