I own one knife with S35VN steel and it holds an edge very well.
I have several liner lock knives, and now have several frame locks, and the frame lock is much sturdier IMO. The act of gripping the knife reinforces the frame lock. There is only the mechanical strength of the steel liner holding a true liner lock in place from what I've seen. Granted though, I've never owned a truly nice liner lock. So maybe the higher end ones are different.
I have one WE knife and it is a fantastically nice built knife. The fit, finish, and machining are all perfect. Mine uses regular torx screws and the blade steel is M390.
I like the quality so much that I just ordered a second WE knife, and it is done in S35VN. Wonderful knives.
Edit: Got an email from the seller this morning that the knife I wanted is actually out of stock. Dang it.