I own Vass and have handled several St. Crispins. I'm not the best one on this site to offer an opinion, but in my limited experience the St. Crispins were decidedly more impressive. That's to take nothing away from Vass, which I love.
I own both and would give an edge to St Crispin on leather quality, finish and overall construction. I'd give Vass the nod on lasts (haven't found a SC last as attractive as U), customer service and value for money.
Unlike other forum members, I actually wear my shoes^^. I had a little walk after the opera, that day. Imagine the crap that Hans and Fritz had on their shoes after they walked back the whole way from Stalingrad to Castle Wolfenstein.