Only because most people haven't used either.
If you are going by build quality and typing, Deck wins without a single doubt for Cherry MX switches. They are built better then any other Cherry board (excluding super low run custom boards maybe) by a longshot... but you pay for it. They are also a little lacking in the style department, so people tend to go with something flashy these days instead.
My personal pick would be a Topre Realforce board. They are built very well, and have a very nice texture on the keys. Apart from that, the Topre "switch" is excellent for typing and anything else... the boards are worth the asking price IMO. The downside is that it's possible you won't like the Topre switch, so it's a pretty big investment if you are unsure... the boards do keep their resale value pretty good though. I think all mine are worth more now then when I bought them lol.