I bought my first pair to fill up an order because they were on sale. After one ride in them, I ordered a second pair. For winter riding they just ad some comfort, eliminate some seams, etc. I'm looking forward to long hot rides in these because I think that's where the real comfort benefit will come.
At the very least, they are way more comfortable than briefs. I cannot speak to durabliity only because I haven't used them much.