Mark Baker quotes Patrick Logan from the service-oriented architecture list:

I ran a short experiment with some folks recently testing interoperability among various WS-* toolkits. What a pain. Very little time was available for actual business value. Then we replaced those WS-* toolkits with simple HTTP clients and servers. After a relatively short amount of time learning the specific APIs we were very soon spending nearly all of our time on business value. We paused periodically to examine what we'd lost by moving from WS-* to pure HTTP. We've yet to identify one thing of importance to us.

Heh. We've been here before - with the OMG and CORBA. Interop problems, confusing specs - the whole nine yards.