From what I've heard, it's expensive AND unreliable.
Like Easy Rider says "From what I've heard, it's expensive AND unreliable." The reason is the spokes "move" While you're riding making a seal job unreliable. I run spokes on my Harley and can't complain after 120k miles.
MV Agusta do it by having the spokes fit to a raised lug on the cast alloy rim. Tubeless have a very big advantage over tubed tyres as they will not deflate immediately you get a puncture, unless its a large rip. Also you can limp a tubeless tyre home with a nail/screw left in place.